In the past few years, I have spoken to local middle school kids (7th or 8th grade) at their "career day". They are all totally fascinated with what I do, because kids nowadays (yes I know I sound old) live their whole lives online and surrounded by technology.
The school where I visit is really average, some rich kids some poor kids, all kinds of backgrounds. The format of this career day is that each class period somebody will come and talk to the class that is somewhat related to the subject - so I usually end up speaking to a math or computer class. In a class of 25, there are probably one or two kids who already know some limited programming (or have made a website). Almost everybody that age is online (all Facebook, a handful of Twitter) and plays console video games. Probably about half have cell phones.
When they ask me questions, it's usually about how to steal their friends' Facebook passwords, conceal their browsing history, or build their own video game. I do spend some time talking about privacy, reminding them that their behavior online can stay around forever and that they should be careful who they are talking to online.
How does it work for a minor using Facebook? Are their accounts public by default? Can they friend and be friend-requested by anybody? Are they linked to their parent accounts somehow so that parents can monitor or approve requests? When they become an adult, is all of the data/content/history going to stay with the account? So when they are 20, friends can see what they wrote when they were 12 if they dig into their history?
(I am not very familiar with Facebook but I do have two young kids who will probably start wanting it soon)
Honestly, I would suggest you get a Facebook account and start playing around with it. The answer to all your questions are "it depends". In part it depends on how Facebook evolves over time, in part it depends on how much they want to curate their content, in part it depends on what their friends do with the content your children are incidentally a part of.
More than any of these, however, it will depend on how well they understand the implications of their actions online. You're going to be in a much better position to communicate about these implications if you understand exactly how they're interacting with their online identity. This means having at least a reasonable understanding of how interacting on Facebook works and, like it or not, Facebook is complicated enough that the only way to understand it is going to be using it.
Minors don't matter, per se, but it it basically illegal to facilitate collecting or sharing information from someone under 13 without enforcing parental control.
The school where I visit is really average, some rich kids some poor kids, all kinds of backgrounds. The format of this career day is that each class period somebody will come and talk to the class that is somewhat related to the subject - so I usually end up speaking to a math or computer class. In a class of 25, there are probably one or two kids who already know some limited programming (or have made a website). Almost everybody that age is online (all Facebook, a handful of Twitter) and plays console video games. Probably about half have cell phones.
When they ask me questions, it's usually about how to steal their friends' Facebook passwords, conceal their browsing history, or build their own video game. I do spend some time talking about privacy, reminding them that their behavior online can stay around forever and that they should be careful who they are talking to online.