So a little more context here: There was a tweet going around Tumblr a little while back from someone involved with the show. It was a picture of the title page of the script for the season finale (entitled "Sacrifice"), with the accompanying text being, "[the end] is gonna make Tumblr fans explode!"

I couldn't tell you if it was real, or even who the guy was that tweeted it -- it was a while ago and I can't find it now -- but yeah. The SPN crew is deliberately working the fandom up into a frenzy for the finale in the hopes that Cas and Dean will finally declare their undying love for each other and close out the season with a hot makeout session.