A few months ago we made note of the public beta of GameLayers’ Passively Multiplayer Online Game, the immensely clever MMO that turns web browsing into a game. Now with 20,000 registered beta users, it’s finally open for public play — go here to check it out.

It debuts with a cool kicker: GigaOM itself is one of the game’s destination sites! If PMOG players visit this blog enough times they win a “KillahOM” badge. “It’s like an Xbox Live achievement that you get based on your surfing habits,” GameLayers’ chief creative officer, Merci Hammon, explained to me. “A lot of players actually change their surfing habits to get all the badges.” It’s also a clever way to get top blogs involved in PMOG — by appealing to our vanity.