I think that it is high time somebody set out some basic guidelines for manners at MySpace.  It's a darn shame when you have to block somebody because of their poor manners. 
First rule of MySpace.  Don't post anything larger than the space allotted. It's sort of like parking your car in their living room.  If you have to knock down the walls then you shouldn't post it.
Second rule of MySpace.  Look around you before you post anything.  Some people put a lot of effort into giving their space a particular style.  Don't post anything  that's going to clash.  When in doubt just post text. Use your words. That's what language is for. 
Third Rule of MySpace. Questions to consider when posting comments on somebodies page:
1) How well do you know this person?
    a) Are you just in the "How do you do" phase?
    b) Is it somebody you've been conversing with for a while on line?
    c) Is it somebody you know in the real world?
Naturally the rules of conversation change depending upon the degree of intimacy between the parties. But if you've just met somebody at the mall you wouldn't strip down to your undies to say hello, would you?  So why would you post a nearly naked picture on the page of somebody you've just met?  MySpace is like being out in public!  Just because your computer may be in your bedroom doesn't make it private.
If you still want to post nearly naked pictures do it on your own page. MySpace is my space.  If I wanted those kind of pictures on my page I'd put them there.  Now that's just me,  if you go to somebodies page and there they are in their undies, then go for it.  Remember rule 2.

2) Why are you posting a comment?
    a) thanking for accepting your friendship.
    b) something on their page that you want to talk about.
    c) sharing a picture or a joke.
    d) advertising or promoting your own agenda.
    e) well wishes
Well, whatever the reason, if you just stick to the first two rules it will be probably not offend.  But in particular, if your reason is c) or d) it is particularly important not to violate them.  For c) it all depends on how well you know the person. If your joke is crude then you'd better know the person well enough to know whether or not they like crude jokes. For d) if you don't want to see your comment be deleted then you should try really hard not to offend.