I don't think this page is necessarily new, but I haven't seen it before, and I think it's a great idea. Over on the official WoW Europe site, they've started tracking player-run and community events on their Community Events page. Slorkuz is even posting on the forums when specific community events are coming up, including their latest, an in-game beauty contest called "Miss Undercity" happening on the EU Darkmoon Faire realm this weekend. I think that's great -- these are completely unofficial player-run events, but Blizzard is still helping spread the word about them on an official page.
In fact, I wish they had something like that on the US page -- if there is one in there, I don't see it linked in the "Community" section as it should be. As an example (and a reminder), Sleeper Cartel is hosting that Dead Man's Party this coming Saturday evening on Perenolde. It would be great for Blizzard to give a little extra official punch (and maybe even some pie) to these player-planned parties.