I suppose that's true. Before Facebook I basically just talked to people over AIM and email lists. I remember setting my status on AIM so people would know how things were going. Initially creating a Facebook account did feel like just filling out your user profile in your AIM account so your friends can find information about you.

Perhaps someone was also mining the AIM data, but that would never have occurred to me to do. I doubt the tools to analyze and monetize it existed yet in any case. I'm not even sure the tools existed to monetize a social network when Facebook started.

It's a kind of weird conceptual leap to be honest, when compared to thinking about just selling ad space or perhaps targeting it based on people's interests.