The big API day is finally here for the New York Times. After launching a series of interesting and useful APIs since last fall, covering everything from campaign finance to movie reviews, they've now released their most important API to date: their Article Search API. With this new web service, developers now have access to 2.8 million articles from the paper of record dating from 1981 through today (our Article Search profile). This API should be a terrific source for a wide range of mashups and third party applications.
Nielsen, the media-measurement juggernaut, announced that it is opening up its API for the first time. Nielsen made the announcement alongside many other groundbreaking launches and promotions as SXSW continues to heat up. With coverage in more than 100 countries, Nielsen maintains a treasure trove of data that developers have long been eager to get their hands on. With the API release, developers can begin to build applications directly off data that is generated and maintained by Nielsen.