It’s just what you’d think: it allows Web developers (like say MapQuest) to use Skyhook’s Wi-fi-based locating to provide better services to visitors. Per the press release you have to give permission to let the app work. When I visited MapQuest’s FindMe page, however, I was asked to download an app from Skyhook and I said not to trust the certificate, so the app was not installed. But, apparently via IP geolocation, MapQuest knew I was in Boston. Other users include Flickr, WeatherBug among a long list (in the PR).
Strangely, the PR does not include a link to how to use the app or fees required. I found the page and Terms of Service. Bottom line: free and advertising free now, but could have ads and require a fee in the future. Limit of 10,000 location requests per day per Loki API key.