There seem to be more people getting into the RSS munging game. Kind of funny to think that there would be a need for people to offer add on services to RSS, it feels too conceptually simple, and yet I know several people working on it, and just found FeedBurner FeedBurner offers a number of services (besides absorbing your bandwidth costs).
They rewrite your element with a unique FeedBurner URL that allows them to track click throughs.
You publish your full feed, and they’ll pare down the content to a specified length.
ala LocalFeeds automatically turn links to Amazon into affiliate links
And several others. Pretty basic.
More interestingly, “authentication services for premium or private feeds” are planned. That could be huge, both in terms of the next generation of RSS, and because unlike the above services it can be genuinely challenging to setup. At one point Bloglines was talking about being in that space, but I think they’ve been keeping busy building an excellent aggregator.