big deal, what do you mean when you say a school should ban Facebook? That they should block it on their own computers in the lab, or they should have the authority to not allow students to have access to Facebook even at home? Clearly, there are schools that do it the second way. And if the parents, and students, know of this rule when they enroll, I don’t see too much of a problem with it (aside from my belief that schools shouldn’t have control over things that go on outside of school). But hey, if the parents are okay with it, good for them.
Regarding your opinion that we must leave children their “innocence” as long as possible: While that’s a nice idea in theory, the bottom line is that they will probably discover the internet and social networking before we wish to “unveil” it to them anyway at an age we feel appropriate. And if we don’t inform them of these things first, and show them how to use it properly, they’ll probably learn about it from the wrong sources, and probably not have too much of an idea of how to use it properly. Too early is much better than too late.
And I’m not sure what you mean about “If they get full exposure to the realities of the world”. They most probably WILL be exposed to the realities of the world. And to fill you in a little, using the internet is considered a necessity to most professional jobs today. Facebook can be a valuable tool for networking, reaching clients, and spreading your product. I use it for a few different things, including school and spreading my work around, and it has helped me greatly.