[gat_sby]

I'd have to agree with this one. Though I like these kinds of hack aggregators, I think yours missing some kind of fundamental product. A favorite of mine is codepen.io – the hacks are organized in a similar fashion but you have the advantage of building natively, forking, and creating collections.

I find the idea of using your engine as a aggregator for github very interesting though. I am not familiar with the github star and watcher apis but there might be a way to push upvotes/favorites/likes to github through interaction on hacksy, though you would still face the battle of bring users over.