FeedFlare™ allows publishers to easily build “interactivity” into the content they create, making it simple for subscribers to tag, email or share their content with others. Publishers can include a variety of services including a live display of the number of comments to each post, the ability to email the author directly and show the number of blogs that link to their item. Publishers can choose to include FeedFlare within the feed itself as well as on their blog or site. This is what FeedFlare looks like in a feed:

Or, check out FeedFlare in our feed and on a few of our blogs.
FeedFlare provides publishers with an easy way to tap into many of the popular social media services available today such as Digg, del.icio.us, Sphere and Facebook. They now can associate other Web services with each content item, bringing them closer to their readers and helping to expand their own reach online, drive traffic to their site, attract advertising or promote a personal cause.
FeedFlare changes the dynamic of how users interact with an RSS feed. Rather than just read content from a feed, subscribers can now take direct actions, such as being able to forward or save an item. In addition, publishers have long needed a way to tie their feed content back to their Web site, creating more of a community while maintaining a constant thread and connection to their content throughout syndication.
The concept of enhancing content feeds is not new. However, with FeedBurner, publishers are not required to make changes to their content management systems each time they want to add interactivity. With a few clicks, publishers can include a whole slew of services. And FeedBurner’s open API allows any Web service to create links that publishers can attach to their feeds, making this a fully extensible and customizable solution.
Publishers wishing to take advantage of FeedFlare in their feeds need only activate the service from within the “Optimize” tab of the application. Here is an example of the simple configuration process. To add FeedFlare to a blog or Web site requires a small snippet of code. Developers interested in building a FeedFlare-able service can reference the FeedFlare Developer Guide as well as the announcement on our blog.
The service is free for publishers and the open API allows developers to create their own FeedFlare services.
Beyond this short list, there are many, many more options that have been developed by third parties. To add any of these FeedFlare units, visit the catalog.
Head over to the FeedFlare Developer Guide or the announcement on our blog. Check out the FeedFlare Catalog for a whole boatload of services you can use right now. Direct additional product-related questions to our well-staffed Support Forums.