Will Sarah Palin be elected President of the US in 2012?

[Vuk]

Isn't it also arrogant, presumptuous and self-important to grammatically correct another person's post just to look better than them?

Nah, just a helpful hint to make his post at least readable so that I do not have to pain my brain just to make sense of it. Strike is fond of making posts that you need to be a code-cracker or Texan to understand.
Seriously, I honestly do not care if someone's spelling or grammar is not perfect, as long as they make an effort not to be offensive. Wouldn't you be a little perturbed if I started SpElInG Licke ThIs? It is one thing in IM, it is something else entirely when you are posting on a forum and have time to write out an at least somewhat understandable post. It is not arrogant to ask someone to stop being so rude.