The folks at Findory are doing lots of interesting things. Gregory Linden has a roundup of reactions to Findory Neighbors. The tool presents blogs related to a given one, by showing a weighted word list of source titles.
Findory Neighbors currently is a nice one shot whizzy hack. I'm probably too much of a wonk for it to be really effective, but transparency would be nice. I have some gut sense of why I get what's in my neighborhood and the weights, but some explanatory data would increase confidence and aid navigation. Transparency in terms of how the connections are determined would be nice, ala PubSub's LinkRanks explanation. Also, longitudinal information, e.g. monthly neighborhood snapshots, would be really interesting.