As location-based apps proliferate, so does the need for umbrella services that can aggregate data from multiple networks. Tweetsii, which is being introduced at SXSW, is one such service that looks promising. The app exploits Twitter 's location-tagged data stream  to tell you who's Tweeting nearby, and it also ties in Gowalla  and Foursquare  data too.
The way Tweetsii's Web site explains the app is almost adorable: "Tweetsii connects people and places across networks. Tweetsii is breaking the wall between the real world and the digital world, where power of the Internet is in real time to have more fun, meet more people, and do more cool stuff ... " But it's undeniable that the app really is trying to break down the barriers between location-based social networking/gaming apps like Twitter and Gowalla and Foursquare because as well as being primarily focused on showing you who's Twittering nearby your location, it also synthesizes all local data from each of these other LBS games into one stream.
And it also goes one further than the simple information-light "check-in" systems that drive Gowalla and Foursquare, by offering its own place-creation code, as well as data-rich upload powers like tagged photos and comments. That means a Tweetsii check-in location can reveal far more to you about who else is checking in there than the simpler systems exploited by Foursquare, for example. It also offers a localized trending topics feed, for hyperlocal news and event alerts.
Essentially Tweetsii is trying to out-Twitter Twitter, while simultaneously lacing in feeds from your other LBS games--and thus turning itself into a one-stop shop for LBS-based social networking. This makes it sound pretty clever...but will the gamble work? It may do, for rabid fans of location-based smartphone gaming who prefer to use Twitter as their primary gateway to the LBS social net world.