But I don’t take Twitter’s statement at face value. Honestly, I think what it means is, “Hey, guy, we’ve been providing a free service for five years, and now we need to make money off it. And if that involves us selling advertising on the clients instead of you doing so, well, you’re going to get hurt.”
That’s a hard thing to hear for developers who have written Twitter clients. Some of these guys are my friends, and my heart goes out to them, it does. But, seriously, the value of Twitter is that it’s a huge network of people who are posting all kinds of interesting things. If you write a client that accesses this data for free, and then you find a way to monetize your client (ads or sales), well, you have to expect maybe Twitter is going to want this money, right?