Add an article section to your web site. People will visit your web site to read and learn new info related to their interests. You may even expand it to allow other authors to post articles.
create the facility for users to sign up for a free newsletter and regularly send them updates on what is happening on your site.
"Really Simple Syndication" is a family of Web feed formats used to publish frequently updated content such as blog entries, news headlines or podcasts. An RSS document, which is called a "feed", "web feed", or "channel", contains either a summary of content from an associated web site or the full text. RSS makes it possible for people to keep up with their favorite web sites in an automated manner that's easier than checking them manually.
Find out what your visitors think about any topic or want from your site
Chat SystemsLet your visitors chat with each other, and with you, too. A proven way to create "community" at your site which will add a new level of interactivity and help to bring people back to your site.
Adding a guest book to your site will allow people to leave you a message or comment.
Video and Audio
upload a video to youtude or google video and display it on your site. Record an audio interview and add it your site so people can download it and listen off line.