I have been pretty poor in the past at letting people know about improvements I've made to Rebrickable. I'd much rather build something than talk about it ;) I will start trying to post regular updates for all the small stuff I usually don't mention anywhere.
Over the last 6 months I have focused on rebuilding the majority of the backend code that deals with calculating parts reuse between sets (i.e. the main reason behind Rebrickable!). I am happy, and quite a bit relieved, to finally announce that this new functionality is now live and I am going to go ahead and call it v2 :)
The competition held last December was a great success with lots of awesome MOCs. We are running another one for April, with a similar theme. Create and submit a MOC using only the parts from any single set of your choice (that meets the criteria below). If your submission gets the most votes at the end of the month, you win $100!