Flickcurl is a library for implementing the Flickr API in C. This library supports the entire Flickr API, including functions for browsing, searching, and uploading photos and videos. It comes with a program called flickrdf that turns a photo's metadata, tags, machine tags, and places into RDF triples descriptions.
This week, 500px cryptically announced the 500px API would no longer be available for free. The announcement hints that the API will continue to be available for a price, but no pricing tiers or models have been published. The announcement was made via Hacker News and developers are speculating.
The most significant recent development for Flickr has been the introduction of video into what used to be a photo-only service. The API has been updated with new features that should appeal to developers.