Love how Josh Beil gets to the guts of Facebook's value. Its Newsfeed + Scale. I see the openness as one way to create valuable applications but not the only one (and potentially noisy to customers). Apple doesn't need it.
If you can build an engine for passive communcations between people like Newsfeed and have a level of ubiquity you can change lives. Tivo, cellphones, major retailers, airlines, hotel chains, governments, car makers can all be players. Facebook is a gateway drug.