The FeedBurner team announced SmartFeed today:
SmartFeed creates a subscriber-aware version of your feed that intelligently deploys the right version of your feed to the appropriate subscribers. Today, SmartFeed understands the capabilities and limitations of syndication readers/aggregators and on-the-fly transforms your source feed to function in all of the readers and aggregators we know about.
Publishers can push out one feed flavor (like, say, Atom), point the reader to their FeedBurner feed, and have it automatically tuned for their reader's aggregator. And as Dick Costolo writes in his post, the "possibilities for subscriber-tuned versions of your feed via SmartFeed (based on parameters that you, the publisher, make available) aren't lost on us either."