FeedBurner

FeedBurner was a pay services previously, now it will be free:

FeedBurner PRO
FeedBurner is a Chicago-based company, a News feed management provider launched in 2004. Its Web-based tools, provides custom RSS feeds and management tools to blog advertising network, web-based content publishers, podcaster to help promote, deliver, and monetize their content on the Web and make feed-based content more accessible and manageable for its end users.

Google makes another acquisition worth $100 millions.

The acquisition will allow the search engine giant to expand its online advertising into the fast-growing world of direct feeds to internet browsers. The FeedBurner sends podcasts, blogs, news, articles and advertising to browsers using tools such as RSS or as you say Really Simple Syndication .

In year 2006, Google achieved more than 99% of its $10.6 billion revenuefrom advertising and listings. Google is very agressively expankding it's online content and advertising portfolio and has recently purchased online advertising company DoubleClick and now FeedBurner.