The LocalBitcoins Go SDK by Zach Latta allows to integrate the search of bitcoins via API by locating possible sellers and buyers. Authentication is available at https://localbitcoins.com/api-docs/#toc1
Foursquare has launched Places API for Start-Ups which provides access to Foursquare location intelligence capabilities at a price point between the free tier account and the Enterprise tier account. The Places API allows companies to integrate apps with Foursquare platform data and capabilities.
Our API directory now includes 239 messaging APIs. The newest is the Parseco API. The most popular, in terms of mashups, is the Twilio SMS API. We list 169 Twilio SMS mashups. Below you'll find some more stats from the directory, including the entire list of messaging APIs.