FeedHub reports that Safari 4 Developer Preview (released today on ADC) is Safari 2, and warns that it may not work correctly. While there may be issues between FeedHub and the DP (although my brief exploration didn't reveal any), it might be worth updating the text or modifying the detection code.
I read that you guys are using a select-and-mutate algorithm approach to customizing content feeds for each person. Sounds cool, but how does it work? Specifically, how does it ensure that it won't drop stories that I will like along with the stories I won't?