Multiplayer gaming IS social software -- and a fascinating development in this genre is the emergence of location-based cellphone games like BotFighters (the grandaddy of the genre, launched in 2001) and Undercover (launched in 2003). In these games, cellphone-toting urban warriors take to the streets of their city to search for clues, complete missions, and engage in battle (and conversation) with their fellow players. Each game overlays a virtual 'gaming grid' onto the physical layout of the city, and tracks the players' location within that grid using the built-in GPS of their cellphones. This genre is starting to mature -- as evidenced by hybrid lifeforms that are emerging. My current favorite is Mogi, Item Hunt, a Tokyo-based game where the core game mechanic is collecting and trading (rather than fighting). Using a live map (shown at right) as a guide, players move through the streets and 'pick up' virtual items with their cellphone interface. The goal is to amass points by completing collections -- and in addition to collecting items on the streets, players can trade items amongst themselves to complete their collections. Mogi also includes a buddy-based messaging service, and a mechanism for messaging any player who's online using the gaming grid. For a user-centric glimpse into what makes this game so compelling, check out this blog post from a Mogi player. Mogi also includes a full-featured Web-based game interface (shown at left) -- which means that logged-in players can communicate and trade objects seemlessly, regardless of whether they're using a cellphone or computer. THIS ROCKS -- I'm thrilled to see smart, creative developers experimenting with trans-device gaming experiences, which I think will be huge. If you know of other entertainment experiences that offer cellphone & web-based interfaces to the same data set, I'd love to hear about 'em. (psst -- here's a little secret I discovered: if you want to check out Mogi's web-based interface, type in 'test' for your username & password and have at it :-)