I've occasionally run into some bugs with the /hn tags on unscatter.com, over all I've found it a pretty useful addition since I've added it. /hn has already made it to the list of tags I use for my daily search on unscatter.com http://www.unscatter.com/search/?q=riak+%2Fdate&t=mongod...
The best part was I'm willing to bet unscatter.com among the first entries. I believe I had all 3 tags available about an hour after the contest started.
Really impressed with ThriftDB. Wish I could remember the name of the API based crawler I saw recently. The 2 together could be a pretty good hosted search experience.