No one is arguing they aren't in their rights to do this. I mean sure a lot of people are indignant about the fact that Twitter became what it was through the ingenuity of the developer community, and without them Twitter would never have grown to its current size, but that's neither here nor there.

The bottom line is that Twitter's communications make it clear that they are grasping at straws for their profitability and that no developer is safe if they think you are capturing too much value. Obviously you always run a risk building on someone else's platform, but Twitter's direction and language around this would make any developer a fool to start anything new on that platform.

But nothing, fundamentally, has changed. Twitter has always been grasping at straws for profitability, and they have always been in control of their platform. Would you have not been a fool to build something on Twitter last year? You would just be betting that they wouldn't introduce limits in the future, vs. knowing those limits today.

Well it's been sort of clear which way the wind was blowing for a while now, but definitely 3 or 4 years ago Twitter was bursting at the seems with developer support for innovation in all directions. It was an extremely welcoming platform compared to Facebook and iOS. Their developer PR has completely reversed that.

Of course if you're cynical you could have called it from the very beginning, but the point is it wasn't wholly unreasonable to believe that Twitter was willing to let developers capture real value in exchange for becoming gargantuan and providing critical infrastructure (ie. the old changing the world thing). Whereas now it's very very clear that Twitter is not willing to share any significant value. They want to capture it all, and they are adjusting the ToS to put them in a position to cut people off at the knees the minute they smell some value escaping from the ecosystem.