Twitter was first to geotag “status” but hasn’t done a lot with it, and Facebook has more substantially put it on the map (bad pun) with Places. We expect a lot more as location awareness technology and consumer awareness continue to escalate.
Similar to the idea behind Facebook Places, location adds a dimension of relevance to the “what am I doing” that is core to Twitter’s user experience. This applies even more to mobile users whose location and status is, by definition, more dynamic.
The idea is that this added dimension of relevance boosts the user value exchange, but also provides triggers for georelevent commercial messaging. The latter is a key part of Twitter’s evolving revenue model.