You should be aware of the CAN-SPAM Act that came into effect in January 2004. The law's main provisions ban false or misleading information in the header and subject lines. You must provide an opt-out method and you must honor unsubscribe requests. If you are sending commercial email it must be identified as an advertisement or solicitation and it must include your actual postal address.

Legislation is being reviewed continually and provisions tightened as people are objecting to the spam invasion which in 2007 was 90% of all email reaching corporate servers. You want to avoid any appearance of being spam as it becomes increasingly unpopular. 40% of US and UK internet users say they do not open email marketing messages because they consider them to be spam. And increasingly, internet users are using the Report Spam button instead of going to the trouble of using the Unsubscribe function, especially as many companies continue to send messages to people who have opted out.

So once you have spent time and energy getting your message ready to send, you will want to do what you can to ensure that it is not going to be blocked by a spam filter. Unfortunately the spam filters cannot always distinguish between spam and legitimate emails.

Keep your emails and newsletters as simple and professional as possible. Excessive use of large fonts, different colors, too many images and not enough text will get your emails flagged as spam. There are many words that act as spam triggers - sex, money, free - and you will want to avoid these in your text as well as your subject line. The best way to check that your emails are not being blocked is to test them by having different email accounts with known spam blockers. Send your emails and newsletters to a gmail or hotmail account and if it ends up in the junk mailbox, you'll know you have some changes to make.

Web hosts may be using spam filtering software called SpamAssassin . This software can be run by individual users on their own mailbox and it integrates with several mail programs. It sends a report on the offending email and allows you to make necessary adjustments if you have used words or formatting you should not have, or included too many images.

You might consider this too time-consuming but open rates have been to increase dramatically by learning to avoid spam filters. And your list increases dramatically also, which is the object of the whole exercise.