Direct promotion via email has boomed over recent years, but has brought with it excessive amounts of spam. If you intend on using email as a method of advertising products and services, ensure you stand behind the products you're promoting.
An effective promotion technique we have found is to combine email with the "article link" strategy. In our e-zine we occasionally put a summary of a product or service, just enough information to stir the curiosity of our readers. The summary then contains a link to the article on our site. The benefit of this is not only that you have a good opportunity to promote the product or service, but while visitors are on your site they may also look at other sections. The advertiser benefits from having highly targeted potential clients visit their site.