Also, the threat of being competed against may never materialize. Facebook can build so many apps, but they won't build them all. This, I think, leads to the r

Also, the threat of being competed against may never materialize. Facebook can build so many apps, but they won't build them all. This, I think, leads to the real litmus test for me: how sure are you that the company is 100% committed to being an open(ish) platform rather than building out its product? The parallels with Microsoft, Apple, and Facebook are quite interesting to explore.