Among the biggest concerns for permission email marketers today are email bounces, spam filters and blacklists - all of which affect email deliverability.

ISPs and corporate domains are battling a huge spam problem. In fact, some reports suggest that more than 50% of all email is spam. To combat this problem and keep spam out of their users' inboxes, ISPs and corporate domains have been forced to employ various email blocking and filtering techniques. As a result, a spam filter could bounce your legitimate, permission-based email back to you, or your mail server might be flagged as a potential spam source. In either case, your messages won't make it through to the intended recipient. In the industry, we call this a "false positive."

Your email deliverability is important because customer acquisition is expensive, and undeliverable emails could mean the loss of customers and prospects that you paid dearly to acquire. Since it is fifteen times less expensive to market to an existing customer than it is to acquire a new one, your efforts to understand and decrease your email bounces - no matter why the bounce occurred - will be well worth your time.

There is a lot you can do to make sure your permission-based email gets delivered:
Become a Trusted Sender
Encourage the recipient to put your From Address in their address book, trusted sender list or approved sender list (whatever the name may be in their email client). Make it easy for recipients to add your From Address to their trusted sender or contact list by keeping it short, easy-to-remember and easy-to-type.

New anti-spam features in AOL 9 and Outlook 2003 are designed to place spam control in the hands of recipients and to protect them from unwanted visual images. In AOL 9 and Outlook 2003, your beautiful HTML layout will appear, but images will not be visible unless you are on the recipient's trusted sender or contact list. As a trusted sender or contact, your email will be delivered and remain exempt from anti-spam measures including filters, challenge response systems or image blockers.

Understand email filters
Check your from line, subject line and email copy, and avoid using language and techniques that might look like spam to a content-based spam filter.
Avoid the following:
Spam-like words
Free, guarantee, credit card, sex etc.

Red text
Get the red out. Red is a loud color and can be hard to read. It is also a spam tactic that may trip an email filter.

All capital letters
Resist the temptation to use capital letters and over-punctuate. When you use all capital letters, there is no differentiation in your words. This makes them harder to read. It COMES ACROSS LIKE YOU'RE SHOUTING, makes your email look like spam and will dramatically increase the likelihood of your email being filtered.

Incomplete information
Your physical address is required by law. Always include your reply email address and your Web site URL, if you have one. Depending on your business, you may decide to include your phone number as well.

Excessive punctuation !!!, ???
This is likely to trip email filters especially when used in conjunction with spam-like words and capital letters.

Excessive use of "click here" especially in all capital letters
Make your call-to-action links more specific to avoid filters.

Excessive use of $$, and other symbols
Again, this tactic is likely to trip email filters. Use just one dollar sign for currency and use descriptive words instead of symbols to get your message across.

No "From:" address
This is a waste of valuable real estate. It looks like spam and will increase the likelihood of your email being filtered.

Misleading (or missing) subject line
Always match your subject line to your email content and never employ spam tactics like leaving the subject line blank or using Re: so that the recipient thinks it is a reply to a previous email. For one thing, it's illegal to mislead recipients, further if the recipient feels duped into opening an email, they will be both unlikely to respond to your offer, and annoyed to discover that they have been tricked.

Analyze your bouncebacks
You should be using an email marketing service that categorizes bouncebacks and provides detailed reports that allow you to view and manage bounced email addresses. Take the time to analyze your bouncebacks and remove hard bounces from your list. It should also be easy to correct obvious typos in your list (e.g. ".con" instead of ".com").
Monitor your "reply to:" address
Many recipients are fearful of using the unsubscribe function as it has been used by spammers to verify an address, rather than as a legitimate unsubscribe. So, be alert to unsubscribe requests coming to your "reply to:" address and permanently remove those email addresses right away.
Use a reputable email marketing service
There's no need to go it alone. There are web-based email marketing services - like Constant Contact - that are appropriate for organizations of all sizes with budgets to match. Some of these services are inexpensive and designed to make email marketing easy for the non-technical user.

Email marketing services take care of the heavy lifting, allowing you to focus on what you do best - promoting your own organization and its products and services. Good email marketing services deliver your emails with proper protocols, develop relationships with ISPs and are whitelisted to be sure your permission-based email gets through. The email marketing service you select should obey the law, maintain strong permission policies and have an active anti-blocking team working on your behalf. Should a problem arise, a reputable email marketing service will get more attention than you could ever get on your own.