GitCred: PageRank applied to the GitHub users/followers graph, implemented in Clojure.
github.com
github.com
I've heard of most of the names top of the list, but #2 was pretty interesting. I had never heard of imbriaco, but it seems like he has just one project: the erlang-textmate. Seems like it's because 37signals follows him, so that gives a lot of juice to his rankings.
Also, looking at this list is looks like the quickest path to the top is to develop open source software for other programmers. Perhaps a javascript library or a web framework or software used by github itself.
We've been seeing a lot more Python recently. Perl and PHP are growing nicely, too.
Back when Google starting gaining popularity it was an order of magnitude better than anything else (I remember using Dogpile to search a dozen individual engines because they were all so crappy).
I feel like the quality of Google search has declined recently, but for something to usurp Google it will need to be an order of magnitude better to get me to switch again.
Stemming (run vs running), synonyms, and other linguistic hackery as well as integration/extension with say Maps (its really convenient to be able to search for say "Starbucks Cupertino" for example).
Search is still moving forward, its just so expensive to make a competitive engine and that the room to improve is getting smaller and smaller.