Julia's right - don't ever send mass emails through your own mail server - not only can you get shut down but you'll end up on a nasty blacklist that can be difficult to be removed from.

Email newsletter programs like Constant Contact, Email Brain, Vertical Response (my personal favorite) etc. all follow the spam laws and provide feedback on the possibility of your email being sent to the trash bin. BUT, no matter how hard you try a percentage will undoubtedly go to waste.

You can advise people who sign up at your site for your newsletter and/or agree to rec'v emails from your company to add your domain to their 'safe list', 'whitelist' or 'allow list' etc. - this will make a big difference in how many get through.

As to the effectiveness, it's like anything else - the more professionally presented, the more value you're actually offering the recipient, the more effective a campaign will be.

I run newsletters for numerous clients with an ad thrown in here and there and the results are always better for clients who provide solid, viable content on a consistent basis. Clients who ONLY focus on sending out ads get a pretty poor return in comparison.

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