Open Graph API seems very clean and it also seems like it doesn't need much documentation... if the API calls actually worked. I haven't used it and I don't plan to start using it given these reports (in the old API there were also quite a few things that break occasionally and take forever to be repaired).
Some syntactic errors are so egregious as to obscure, change, or remove the meaning of a sentence.
Graph API - The Facebook API for querying the Facebook graph
Open Graph Protocol - The "standard" for be able to query meta and classify a particular website.