I don't think the open-source aspect of it was the important difference. Rather, I think the thing that let 2048 become so huge, compared to Threes, is that you

I don't think the open-source aspect of it was the important difference. Rather, I think the thing that let 2048 become so huge, compared to Threes, is that you can show someone a link to 2048, and the moment they follow the link, they're playing it. I think this is an important reason not to dismiss the Web as a platform.