The best email practices should give you the best sender reputation, therefore some things to pay attention may include:

Spam complaints from recipients – Are you generating too many complaints for email you’re sending?

It’s interesting to note that some subscribers may not remember signing up for your list, especially if you mail once in a blue moon. Then again, if you mail to often your email will probably end up in the trash, or the recipient will just hit the SPAM button rather than unsubscribe from your list. To prevent this you should:

Spam Traps – why did you send to this address?

The fast track to a bad sender reputation is sending email to a Spam Trap. Spam Traps are secret, non-published email addresses that catch some list owners by surprise.  A Spam Trap is a valid email address, used specifically to trap unsolicited email or spammers; hence the name Spam Trap. The Spam Trap premise is based on the belief that if the owner or former owner of an inactive email address has not checked email for a quite a while, why are you still sending email to this address?

• Offer a profile page, allow your recipients to tell you their mailing preferences
• Include an easy way to unsubscribe from your newsletters: test the unsubscribe mechanism you’re using to make sure it actually works
• Remove those addresses that want to be removed
• Consider asking the potential unsubscribed member, if they would like to place their account on hold, (instead of unsubscribing) until a time when they are ready to receive your emails again

Your IP address – who are you?

An IP address or an Internet Protocol address identifies the mail server your are sending from.  You can use a shared IP address or dedicated IP address. If you are just starting out with email marketing, having no sending history you might be using a new IP address.  (Or you may have switched to a new IP address if your sending reputation, for whatever reason isn’t quite up to par, which is not recommended over cleaning up your act.)
IP addresses have a great impact on senders’ reputation. For example, with a  brand new IP address, that has no history you may find that until you start sending regular mailings to establish some sending metrics, ISP’s may be suspicious of your intentions and treat your email by:

• Not readily accept whitelisting requests
• Causing deliverability problems with tarpitting
• Block your messages

If you use a service that places you on a shared IP address, realize that the IP will be used for all email that is distributed from that particular mail server.  Your sending reputation will be as good as the worse company’s sending reputation on that IP address.  If the IP is blacklisted everyone on that IP is blacklisted. To avoid all for one and one for all, invest in a dedicated IP address or use an ESP that will put your list on its own IP address, in doing so:

• You will be the only sender on that IP
• You will have total control over your sender reputation

 Authenticate – where are you from?

Email authentication is the process by which an ISP (the mail server recipient who delivers incoming mail to their customers inboxes: i.e. hotmail) can verify the supposed identify of the sender.  While there is no recommended standard for email authentication, there are several ways available to do so.  Some may prefer one method to another; use several, one or none.  Some available Authentication Systems include SPF, SIDF and DomainKeys ( DKIM.).  Messages that cannot be authenticated by the receiving ISP may be:

• Blocked
• Delivered with a tag that the sender cannot be verified
• Or may just deliver the mail with no issues

Invalid Addresses – return to sender

When an ISP receives incoming mail with an invalid address, the sender IP address and domain may be scrutinized and judged adversely based on how many invalid (non-existing) email addresses received compared to functional email addresses received.  A low number of invalids base on total volume is acceptable (<1%) a higher number is not.

Invalid email addresses normally cause an email to “bounce”. Briefly, there are different types of bounces; the most harmful to a list owner is the hard bounce.  Hard Bounces may occur when:

• Recipient address is misspelled
• User doesn’t exist
• Your domain is blacklisted

A hard bounce is normally perceived as a long-term or permanent condition that is generally not expected to clear up any time soon.  High invalid rates may cause considerable delivery issues not to mention a lower sender score.

Consider all the reasons email addresses become invalid and be proactive.  Institute profile pages to allow your subscribers to update their email addresses.  Remove those hard bounced emails.

Welcome Email – Are you building a relationship with your subscriber?

When someone subscribes to your list, send them a Welcome Letter.  A Welcome letter allows you to start direct, personal communication with your subscriber.  By greeting them you can begin your email relationship on a friendly basis and:

• Authenticate their new membership
• Set the newsletter venue
• Inform them how to change their profile page (if offered)
• Explain how they can provide feedback (with a working link)
• Remind them to add you to their Safe Sender List
• How to unsubscribe

A Welcome Letter should support your brand name, not be too wordy or overbearing, just a welcome and a thank you.  A Welcome Letter serves as a reminder, so when your subscriber receives that first email from their new subscription they will recognize you as someone they wanted to hear from and not report you as a spammer.

In summary, the best email practices should give you the best sender reputation. Mail on a schedule or mail to your users preference, use a dedicated IP address, send to only opted in list subscribers (in general don’t buy lists as they may contain a Spam Trap) Welcome your subscribers, use authentication, remove unsubscribe requests and resolve Spam complaints. Keep in mind even best practices may not be enough if your content has explicit language, bad grammar, too many spelling errors, a large file or one big graphic.

Many variables can affect your sender reputation here are a few websites to review so you can see how your reputation is perceived.

Sender Score Tools: – what sender score do you have with ISPs?

Ciscos Ironport SenderBase and reputation lookup.

Barracuda Reputation; maintains a history (and real time information) of IP addresses for both known spammers as well as senders with good email practices.

Return Path’s Sender Score; score will provide you with information about where that source stands in comparison to other email senders