Still, he might have still been treating Facebook as a goofy side project at this point. And IM chat doesn't express jest or joking around.
Call a spade a spade.
For one thing, just because a lot of kids are immature doesn't mean that they have a license to break the law. Joking obviously isn't a violation of the law, but breaking into private e-mail accounts is (18 USC 1030).
For another, Mark had already been formally disciplined by the Administrative Board for Facemash when he wrote these, so he clearly knew better.
Aruging that Facebook has the right to misuse people's content just because they provide it is clearly wrong.
In addition, there are five people including myself who ultimately filed legal action against Mark and/or Facebook, Inc. because of what happened at Harvard.
Lastly, at roughly the same age, I ran the same core product at the same time in the same place with the same name with the same people's information, and I didn't do that. I didn't joke with my friends about it, I didn't make fun of my users, I certainly never intended to abuse people's trust, and I never did. One of those users was Mark and I have his SHA-1 password hash sitting in my database, as well as his cell phone number--but I'm not going to share it with anyone, nor have I ever. Clearly it's possible to run such an operation in a different way than Mark.
"Call a spade a spade" indeed.
People joke about doing things they would never dream of doing. Heck, people lie about doing things to show off to people all the time - especially when younger (though not exclusively, by any means)
Are there any examples of him actually misusing this data?
There are people who are sticklers for every rule from an early age, and then there are those who do impressive things. The overlap is very small.
You are too personally invested in this situation to act rationally.
That might be true AND still not excuse a given behavior.
If I had vast power, I too might do a number of unpleasant things too... It's up to you to folks stop me... AND I'm OK stopping someone else at the same time...