RSS feeds are very useful for frequently updated sites; namely blogs. People often have feed readers to watch multiple sites at once. They then only really click to visit a site if a new post or update shows up on the RSS feed.  How they work is…Basically, you just have a file on your server. Anyone that visits your site can tell their “RSS Reader” to check it every time that they use their reader. So it’ll download and display the contents of that file in their reader–if their reader understands the contents.

It can also be used for things like putting a “Top 10 posts on [blog]” which can be displayed on other sites when they parse the RSS file using PHP and output the contents onto their own layout.

I highly recommend Feed Burner as a free service to compile all your feeds. It provides tracking and stats as well as other services for your feeds. If you are running a blog, you’re really shooting yourself in the foot if you don’t provide an RSS feed.

Adding a feed from your own site to your MyYahoo can also give you a leg up on getting your site crawled.  My hip hop blog does well with rss when I do updates! Maybe 100+ more a day when I have an update.  So yeah, they do work.