Whether you send a single innocent email message or blast a spam-like email to thousands of recipients – your message will have to go through a number of obstacles. Here are four checkpoints any email has to pass successfully in order to land in the recipient’s Inbox:

Sender’s Email Software >> Sender’s ISP / Webmail Provider >> Recipient’s Email Server >> Recipient’s Email Software.

The chart below illustrates an email’s road to the recipient’s Inbox, step by step. It shows the obstacles the message undergoes at the sender’s ISP checkpoint (attachment size check and email sending frequency check), a thorny way through the recipient’s email server (attachment check once again; sender IP check against the current blacklists; virus/ spamware/ malware check), and the spam / virus check on the recipient’s computer.

Point #1: Sender’s Email Software

Once you hit the Send button in your email client or Webmail interface, your message starts its journey. Make sure you type the recipient’s email address correctly so the message will have a route to follow. Don’t leave the Subject field empty – this may trigger spam filters on the recipient’s side.

Point #2: Sender’s ISP or Webmail Provider

Once your message reaches your ISP or Webmail provider, it may suffer the risk of being blocked. One of the reasons can be attachment size exceeding the recommended limit, or using a file format restricted by your Internet Service Provider or Webmail provider. Your message can also be blocked if you have sent too many messages today, so make sure to contact your ISP and learn their limits before you start a serious email campaign.

Point #3: Recipient’s Email Server

On the recipient’s email server, your message may undergo a repeat attachment check. Attachment restriction rules may vary from provider to provider, so be sure to abide by the rules of both. Apart from the attachment check, sender IP may also be checked against the current blacklists. Besides, your message may be checked for viruses and malware and may be rejected if any suspicious links or attachments are detected.

Point #4: Recipient’s Email Software

This is where spam filters and anti-virus software work hard on the recipient’s side. As a result, a great many emails are being sifted and yours may land in the Spambox. It’s a well-known fact that spam filters often make mistakes and trap legitimate messages.  If you don’t want important mail to be mistakenly killed by spam filters – use and recommend EmailTray, a standalone email client with powerful email prioritizing features.

You can feel free to post the chart on your website using the code below:

<a href="https://www.emailtray.com/blog/emails-road-to-heaven-aka-inbox/"><img title="Chart: Emails Road to Heaven aka Inbox " src=" https://www.emailtray.com/blog/wp-content/uploads/2012/09/emails-road-to-heaven-inbox-preview.jpg" alt="Chart: Emails Road to Heaven aka Inbox " width="601" height="384" /></a>
<a href="http://www.emailtray.com">EmailTray, Free Email Prioritizing Software for Windows</a>

Email is definitely not dead as a means of communication and a marketing channel, as web surfers keep on subscribing to newsletters, reading them and buying from them.

Why are email newsletters still so popular? The answer is simple: they sound personal and cause emotional attachment. According to the Email Newsletter Usability Report issued by the Nielsen Norman Group, users have more emotional reactions to the email newsletters rather than to website content. As stated in the report, newsletters feel personal because they arrive in users’ inboxes and users have an ongoing relationship with them. Sixty-nine percent of users said that they look forward to receiving at least one newsletter and most users said a newsletter had become part of their routine.

Reasons for Poor Email Delivery

An email message normally makes a lengthy trip before it reaches its final destination – the recipient’s Inbox.

After the “Send” button is hit in the sender’s email client or after an automatic script starts sending bulk mail, the message is routed to the sender’s mail server. This mail server might block the email due to a lengthy email attachment (e.g. most Webmail providers have a restriction of no more than 25 MB per message), or because a sender has reached a daily limit of sending emails (e.g. some email providers would limit you to no more than 100 emails sent per day).

The next pit-stop is the recipient’s mail server, which might bounce an email because of a lengthy email attachment, because the sender IP or domain is blacklisted or viruses and spam-like content are found in a message.

Even if the message goes through the sender’s mail server and the recipient’s mail server without any problem, it might be blocked on the last step of its trip to the recipient – the recipient’s email client. Most email clients have built-in spam filters, and these filters may block email because of viruses and spam-like content found, or use any other filtering methods.

Tips to Retain Subscribers and Improve Your Email Delivery Rates

Take care of the contents of each message and your writing style

1. Address to the recipient personally
At the beginning of a message, use a proper salutation and address the recipient with their real name, not a generic noun. People love to read and hear their name – this makes them feel comfortable. At the end of the message, make sure to use your real first and last name, not just a company title or a fancy nickname.

2. Make your newsletter interesting and exciting
Step aside and think if you would ever subscribe to your newsletter if you were interested in your topic. Would you have benefited from this newsletter much? Be sure to add value and meet the expectations of your subscribers; do not use email for a sales pitch only.

3. Make it emotionally appealing
People are reached through their emotions. In newsletters, this rule works especially well, so do not pass by the opportunity to appeal to your newsletter subscribers.

4. Build a relationship
Do not think of email as a one-time blast campaign. Do think of it as if you were in a long-term relationship with your customer. Retain your customer, send follow-ups, remind them who you are and why they are subscribed, ask for feedback and communicate. In other words, maintain your relationship.

5. Send newsletters on a regular basis
Sending a newsletter 1-2 times per month is perfect. You may set your own newsletter frequency – from a weekly to a daily newsletter. Everything depends on the industry and the way you position your newsletter: hot news, useful tips, product updates, etc. Also, let your subscribers know what the frequency of your emails will be.

“Dress up” your email well

6. Use quality design
Avoid using third-party templates or email template generating software. Hire a good web designer or outsource this work to have it done for you decently. Do not copy-cat someone’s email templates even if you find them pretty. Make your newsletter look and feel professional and credible.

7. Avoid complex HTML-elements and too much graphics
Some HTML elements and excessive graphics might trigger email spam filters, so you’d better keep away from complicated designs for the sake of successful email delivery. A simpler email is definitely better than undelivered email, right? Avoid using too many closed tags, tables, colorful backgrounds, JavaScript and web forms.

8. Test before you send
Before sending your message, make sure to test it under different circumstances. See how it looks in different email clients and the most popular Webmail interfaces. Make sure all links work OK and that all images render. Test the unsubscribe links and, to be sure, check your spelling.

9. Use an email address with the domain of your website
Do not use your “@yahoo” or “@aol” personal email address. You have a website, so you should already have email accounts set up under that domain. Do use these email addresses to sound credible.

10. Make it easy to unsubscribe
At first glance, this piece of advice sounds contradictory… Of course your aim is to increase your subscription rate, not increase your unsubscribe rate, right? However people get most irritated with those newsletters that are: non-legitimate, boring and… hard to unsubscribe from.

Take care of the technical details

11. Configure reverse DNS entries
Many email servers are configured to reject incoming emails from any IP address which does not have reverse DNS. If you host multiple domains on one email server, just setup reverse DNS to point to whichever domain name you consider primary.

12. Create a proper SPF record in your DNS
SPF allows the owner of an Internet domain to specify which computers are authorized to send mail with sender addresses in that domain. If you publish an SPF record for your domain, spammers and phishers will be less likely to forge emails pretending to be from your domain.

13. Sign your mail with DKIM
Digital signatures ensure your emails’ authenticity. Make sure to sign your mail with DKIM (DomainKeys Identified Mail) to take responsibility for the messages you send.

14. Review feedback loop emails on a regular basis
Feedback loops are one of the ways for reporting spam. Feedback loop emails will let you know if there are unhappy users who hit the “This is spam” button and resolve the issues.

15. Monitor blacklists and request removal if you’ve been listed
You can set up alerts on blacklist updates to track if you’ve been listed. Don’t panic if you do get listed one day. If you haven’t abused the rules, it normally takes a few emails to the ISP abuse address to get the things resolved.

General after-sending tips

16. Track your sender score
Most popular ISP providers and spam filter developers calculate a sender score for each volume email sender. In case any violations are detected, they decrease the score. To have no problems with email delivery, do all you can do to improve your sender score.

17. Ask readers to add your email address to whitelists
To keep your sender score and delivery rate at a high level, kindly ask your readers to add your email address to their whitelists. Explain to them why it’s important and let them know how easy it is to do.

18. Cleanup your subscriber list on a regular basis
One of the quickest ways to get on blacklists is to keep sending email to dead addresses. So it makes sense to look at the bounced emails you get, and remove them from your list ASAP.

19. Track your email delivery
Watch newsletter bounce activity and delivery receipts. Analyze the reasons why some emails haven’t been delivered. Work with the ISPs to get yourself off blacklists.

20. Never purchase email lists
Untargeted. Unsolicited. Uninterested. Do you really like these attributes? With purchased email lists, these attributes may end up describing your email campaigns. Earn new subscribers using effective and time-proven methods – share content, build a community and gain each reader’s interest.

To ensure that your recipients do not get your mail mistakenly trapped by spam filters, recommend that they install EmailTray – a smart email client for Windows and Android smartphones. EmailTray tracks mail from all accounts and sorts messages using a smart proprietary algorithm. Even if a legitimate message gets trapped by mistake EmailTray will rescue it from the Spam folder and notify a user about it.

According to the Global Email Deliverability Benchmark report issued by Return Path in March 2012, worldwide inbox placement rates declined sharply in the second half of 2011 to a record low of 76.5% globally, compared to 81% in the first half of 2011. This means a lot more email has been heading to the spam box.

Nowadays it’s not enough to create a marketing message, embed pictures and blast this to a large email list. Email deliverability is the issue that bothers marketers a lot. ISPs and Webmail providers, both on the sender side and the recipient side, may block your message for many reasons; and one of them is email attachment size and format.

Email Attachment Size Restrictions

In a race to get the most devoted users, four major Webmail providers (Gmail, Windows Live Hotmail, Yahoo! Mail and AOL Mail) currently have the same restriction regarding the total size of a sent or received message. You can send or receive messages of up to 25 MB each for free.

Some Webmail providers and commercial Email Service Providers will allow you to send larger email messages. However there is no guarantee that the recipient who uses a different Email Service Provider will be able to receive your lengthy message. The attachment size limit of the person receiving the file does matter; if your file is over their limit for receiving, the email will be rejected.

Gmail
With Gmail, you can send and receive messages up to 25 MB in size. However it’s not a good idea to send larger attachments to people who might be using the other email services with smaller attachment limits. The good news is that Google offers Google Drive cloud storage service, which adds an extra 5MB of storage to your Gmail account.

Windows Live Hotmail
Windows Live Hotmail has a restriction of 25 MB per email message as well. There is a workaround however. You can take advantage of the Microsoft’s SkyDrive service, an online cloud storage service that is available to everyone with a Windows Live Account. You can upload large files (up to 7 GB for free) to SkyDrive and share them with your contacts.

Yahoo! Mail
With your Yahoo! Mail account, you can send and receive emails up to 25 MB.

AOL Mail
AOL Mail restricts messages to no larger than 25 MB.

Mail.com
With the emailing service offered by Mail.com, you can send attachments of up to 50 MB.

GMX.com
With GMX Mail, you can send attachments of up to 50 MB as well. Besides, GMX File Storage offers you another 2 GB of space for your documents, images and media to share with your friends and family.

As for the Commercial Email Service Providers, the limits that the recipient’s server has on attachment size may vary from email service provider to email service provider.

Note: The total email size includes the message text, headers, embedded images and attachments. That means that you must take into consideration the total size of the message, not the attachments only. If, for example, you are including a high number of embedded images with your email message, then your attachment size is going to be restricted by the size of the message including the embedded images.

Restricted Attachment File Extensions

Sending the following file types is OK with most of the Webmail providers: word processor or spreadsheet documents, audio files, image files (.bmp, .jpg, .gif, etc.), and web pages saved as HTML files.

It is definitely not a good idea to attach executable files to your email messages, as they might be blocked by email providers or the antivirus software installed on your recipients’ computer.

Gmail will not let you send or receive executable files (such as files ending in .exe). In addition, Gmail does not allow you to send or receive files that are corrupted. Gmail won’t accept these types of files even if they are sent in a zipped (.zip, .tar, .tgz, .taz, .z, .gz, .rar) format. If this type of message is sent to your Gmail address, it will be bounced back to the sender automatically.

With Yahoo! Mail, you can send all types of files as attachments, including word processor or spreadsheet documents, audio files, image files (such as .bmp, .jpg, .gif), and more. There is no restriction openly stated by Yahoo!, however they kindly ask you to be particularly cautious about executable files, which end with these extensions: .exe, .com, .vbs, .lnk, .pif, .scr, .bat.

Just like with the Gmail Webmail service provider, Windows Live Hotmail will block any email message including executable files.

AOL Mail is quite liberal with its users as far as it concerns email attachment extensions. If the attachments are of the file types .exe, .scr, .com, .msi, .bat, .pif , .vbs, .cpl, or .cmd, AOL Help advises you to compress them before sending. To do this, you can use a third-party compression program such as WinZip.

Email Etiquette for Attachment Sending

• Delete attachments from forwarded messages when you only want to share the text. Forwarding attachments for no reason is not polite.
• Ask before sending. It is not OK to include a spreadsheet, a document or a presentation file without the recipient’s consent, especially if this is the first email message you ever send to a person. You can only send attachments without preliminary asking when a sender knows you well enough or expects attachments from you.

• Do not send files larger than 25 MB. If the file that you’re trying to transfer exceeds 25 MB, you’ll need to either compress the file or split it into smaller parts. Another option is to share this file using a cloud storage service, e.g. Google Drive, SkyDrive, Dropbox, etc.

• Scan the file you are going to send for viruses. Sending an infected message to a customer or business partner may ruin your relationship once and for all. Always have your Anti-Virus software running, and make it a rule to scan outgoing messages for viruses.

• Do not send attachments after business hours. The chances are that the recipient will be checking mail via a smart phone. Downloading and viewing this attachment might be a pain.

For more tips on safe email sending etiquette, read our post about business email etiquette rules.