Is it safe to show your face online?

I'm confused how you're ranking them. It seems like you're saying:

Youtube is the riskiest
Myspace is the middle
Facebook is the most secure, but still risky (of these three choices)

But you may also mean the exact opposite.

Regardless, I would argue that this order is true. Youtube, anyone can access your material, and infact you promote your material and want as many people as possible to access it!

Myspace has some ways of limiting access...but I used to use Myspace until I figured out how easy it was to get into a person's 'private' information. The seemingly random photograph names are actually quite logically named, and there is some code system that allows you to access someone's photos even if they are not private.

Facebook is similar but has a much tougher system to crack. Infact, since it's dynamically generated, random guessing may lead to some solution and yet there is no predictable, systematic way of guessing what a person's photo URL will be (as in Myspace).

Regardless, I now use Facebook, but I don't post pictures! Except for one humerous one I had at one point, where I pasted a Super Mario Bros. [?] block over my face to replace Facebook's default ? picture.

I also remove all tags of myself from all pictures I may be tagged in. If anyone needs to access my facebook, they know what I look like anyway.