The marketing folks at Skyhook passed this along:
Today Skyhook Wireless is rolling out a private beta for MyLoki, a new service for Loki. Using your current location, MyLoki can show friends where you are - check out my email signature for an example. [It said the person was in Boston.] We've also added a Facebook application, and integration with Jaiku or anything that supports GeoRSS.
MyLoki keeps your friends up to date on your location, helps keep track of where you've been, arrange get togethers with friends in your current area, and much more.
You can request a invite code
here. Loki uses wireless hotspots locations to determine location.