Depends on what you think of as free/small. My startup, http://reviewsignal.com http://reviewsignal.com is a free service people can use to look up web hosting

Depends on what you think of as free/small. My startup, http://reviewsignal.com http://reviewsignal.com is a free service people can use to look up web hosting companies. it's automatically tracking all the tweets about major hosts and publishing the results. It's profitable and free, but was a lot of works (not sure how small it really is). I've also built a lot of tools closer to what you're describing, things like http://listmanipulator.com http://listmanipulator.com and http://domainling.com http://domainling.com but none of the smaller projects come anywhere close to being a sustainable living.