We're targeting releasing the Synchronize.TV APIs in June of 2011. There are two APIs; the first is the synchronization and recognition API, the seond it the context API. Full documentation will go on this page when it is available.
Synchronization and Recognition API (SRAPI)
SRAPI provides information to second screen devices about what programming is on a specific connected TV. SRAPI is accessed by passing the set top box (STB) or connected TV UUID (universally unique identifier) to a web service. The web service then passes back the unique program ID of the specific show that is currently on the associated STB and the current offset in seconds from the beginning of that show. We may make additional metadata about that show (plot, cast, etc.) optionally available.
Context API (CAPI)
CAPI provides information about the content of programming in the form of keyword density used in a given time window on a channel or in a specific show. There are two ways to use CAPI. You can pass a network ID and a time window to a web service and we return the words used in that window. For example you can query for words used on CNN in the last 5 minutes. Or you can query a program ID and a time window (independent of network). An example might be to show me the words used in the 14th minute of a specific episode of Law & Order.