1) The fic had Jensen reading J2 fanfiction. He likes it and starts writing himself. Jared reads it and knows Jensen's the author, because there are so many details about the ep they're filming nobody else would have known. 

Found: A Major Re-Write by emerald_angel9
2) I could imagine this fic, but maybe it was more than just an idea in my head. It's a J2 version of the movie "You've Got Mail".