Many people read the posts for information and get annoyed at blatant advertising. You can, however, add a tasteful signature file to your e-mail. In this file you can add a few words about your site and the URL in case the reader might want to visit. If you enjoy writing, you can publish your own newsletter or write articles for niche publications. Don't forget to send out press releases every time your company does something newsworthy.
Publicity is important.
If you enjoy speaking, you can offer to speak or teach or do radio and cable TV talk shows. Your audience may be interested in visiting your web site for more information. As an affiliate, you would be rewarded each time a customer buys one of the sponsor's products at your site. Then of course, there's always paid advertisements. That was quite a journey through web promotion ideas.