The premise is simple, you tell Fire Eagle where you are and it offers you a veritable smorgasbord of services based on your location. Users will be able to enter their geo information via IM, GPS-enabled phones, and even Facebook.
So if you're looking for a good pub in the locality you'll be given the address of one nearby and not the site of The Blue Lion in outer Mongolia - unless you're actually living it up in outer Mongolia that is.
At first glance it all seems a tad Orwellian, it's not nice thinking that the local cat burglar can know when you're not at home. But don't worry as tracking can be turned off whenever you want and Yahoo says that all geo data deleted by users will be immediately removed from its servers.
Sadly the beta version has almost no functionality, all you can do is give your location which Fire Eagle notes and then puts on an embedded map. Also, there seems to be no interface to check out your friends' location.
On a brighter note, Yahoo is offering API kits in five different programming languages, and already has user authorization protocols available for web, mobile and desktop applications. So, the future looks bright for Fire Eagle.