The Reddit Lisp SDK by jperson allows developers to integrate the Reddit API into their Lisp applications. Code examples are included in the documentation.
Twitter added some features to its Search API to bring it to par with the flagship Twitter API. The API brings the context of a tweet to the place where users likely need it most.
Facebook introduced v5.0 of both its Graph and Marketing APIs. Most of the changes were to the Marketing API. The Marketing API includes a brand new API: the Ad Volume API. The API will help advertisers understand the number of ads they are running, and help comply with upcoming policy changes.