Why not? It can make sense in a lot of ways. I think that without a free API the service will become far less relevant. Sure, you could monetize access to it,

Why not? It can make sense in a lot of ways. I think that without a free API the service will become far less relevant. Sure, you could monetize access to it, get a few cents here and there. But far fewer tools and sites will integrate with Twitter from now on. Twitter needs money, yes, but I doubt they will grow again with decisions like this.