Update: It was a long time since the post, so it does not work anymore... openkapow went commercial and parsing things need constant support which I am reluctant to do. Anyway, there should be a better way to do this now. Let me know if you find one ;)
It's been quite some time since I've read about various RSS mashups engines. Until today I considered them quite useless, however.
But not now. I've changed my mind a moment after I managed to create this thing. Here is an example of comments for my Russian rare blog.
It serves all comments of a specified user of LiveJournal blog in a single RSS feed. I wanted such a feed for some time already and today is the day.
Pleas note the it works for some, but not for all users. It fails on collapsed threads, etc, etc.
Some background: the feature uses openkapow to turn single entry comments into the feed and then Yahoo! Pipes to aggegate them into single feed. I tried to use Dapper instead of openkapow, but it turns to be quite buggy and not really as robust.
Well, Google's Mashup Editor is yet to try!