The CityGrid Ruby SDK by CityGrid provides installation, configuration, and sessions as part of the resources included on GitHub. Although still in development, author recommends to use the latest development. To start, obtain a publisher code at http://developer.citygridmedia.com/
Microsoft's latest version of its search API (our Live Search API Profile), which was released last November as a public beta, seems to be gaining quite a bit of momentum. According to a recent post on the Live Search Blog, the API is serving more than 3 billion queries per month, more than 5,000 applications to use the API, and queries from third party sites account for 80% of the API's query volume.
Factual recently announced a new SDK that enables third party apps and services to pull location data from its massive database and trigger certain actions in response to data points like location, environment, movement and more. The SDK is easily used through the Garage Web UI.
Life on the web is full of search terms and human filtering. Even good results often require some effort to determine which has the information we seek. There are several services attempting to help with this problem and they're making their applications available via API.