Location-based services appeared here, there, and everywhere at the Mobile World Congress in Barcelona this week, as service providers maneuvered to take advantage of the increasing number of mobile phones shipping with integrated GPS (Global Positioning System) modules. Many of the services put the emphasis on finding your friends, not finding your way, as GPS evolves into more of a social tool.

Yahoo announced a service called oneConnect that will to alert you when contacts arrive in town, warn you what mood they are in and show you a list of their recent e-mail messages that you have left unanswered. Yahoo intends to collect this information by combining status updates from sites like MySpace with GPS data from mobile phones and other information from Web mail and instant messaging services, a kind of aggregation for social networks. The service will go live by June, and will work with services including Google's Gmail and GoogleTalk, AOL Instant Messenger, and Microsoft's Outlook Web mail, said Marco Boerries, executive vice president of Yahoo's Connected Life division.

Communology, of Cologne, Germany, promoted a similar notion of social-network aggregation. Its Mobile Mash-Up can help sites like Facebook or Xing offer mobile users the ability to locate friends or tag photos with information about where they were taken. Communology sells "white label" services, using its Live Media software platform to build social-networking services for other brands.

Linking up with Facebook is a strategy that also occurred to Wayfinder: it now offers a GPS widget for Facebook users called LocateMate. The company also introduced a forum for users of its software to share favorite routes and locations at MyWayfinder.com, with links to digital mapping tools such as Google Earth and Microsoft Virtual Earth.

GyPSii showed a BlackBerry client for its mobile social-networking service. It already offers versions for handsets running Symbian OS and Windows Mobile. The service allows users to share photos, videos and other information, tagging it with location data. Last year, GyPSii, based in Amsterdam, acquired Finnish mobile phone manufacturer Benefon, one of the first to build GPS modules into mobile phones.

One of the strangest location-based mobile social networks revealed at the show allows users to share information about ... public toilets. MizPee.eu offers reviews of toilets in Barcelona, London, Paris and Rome posted by community members, with ratings for cleanliness and cost. Showgoers hoping to use the site to beat the long lines for toilets on site were disappointed, though: the nearest one listed is 1.45 kilometers from the showground.