I was thinking of doing something like this last year but never got around to it. I wanted to build the user experience around commenting on reddit using eg #b

I was thinking of doing something like this last year but never got around to it. I wanted to build the user experience around commenting on reddit using eg #buythis or #dontbuythis anywhere in a comment and it'll hopefully attract attention and spread. I think there's especially potential with movies and games on itunes and amazon.