I think to understand @daltonc's strategy with join.app.net, one should be familiar with Thomas Schelling's concept of 'precommitment':

http://en.wikipedia.org/wiki/Precommitment

Note that the 'textbook' examples of precommitment involve the burning-of-bridges or burning-of-ships-at-the-shore.

If there's any hope of an alternative to Facebook/Twitter at this point, given the incumbents' long head-starts, it's going to be a 'zag' to the incumbents' advertising-supported 'zig'. Caldwell might not have gone into his Facebook meeting fully intending that sort of confrontation... but by the time he left, the choices were stark.

I thus view Caldwell's anecdote not as a complaint, "boo-hoo I was wronged", but as him sharing a difficult lesson: that Facebook's model makes it impossible for Facebook to be a magnanimous platform steward. Perhaps Caldwell should have seen the writing on the wall earlier, but many exterior-platform shops are missing the same point, as evidenced by the surprise and indignation after each new consolidating move by the platform proprietors.

Perhaps Caldwell could have intuited the reality beforehand, and written about it in abstract terms. The anecdote illustrates the problem, in a way that far more independent developers will understand.