“It can always be traced right to you too.”
Generally, but not always. There are plenty of ways to post things to the internet that could never be traced back to you, but ordinarily, people don’t bother to make use of them.
Yes, of course. For you or I it is quite simple to do really... just build a nice Yagi antenna, 'Wardrive' using the 'Backtrack' OS. If you really want to screw them up use chained proxies... easy enough to find...
For beginners, start with a Firefox Proxy plugin.
Then go to Proxy List to get a list of fresh proxies and you can post from Siberia. Really screw them up and use an http proxy on top of it... while wardriving... you can never get caught once you shut down the connection.
Of course, you can post from an Internet cafe... but that's how they catch quite a few wanted fish... but many get away, especially if that Internet cafe is in Russia and you never use the same one twice.
It's an awful lot of trouble to go through... just a lot easier to advise people not to shoot off any comments that can damage themselves.
Then there's TOR...
I would never thoroughly trust a canned solution - could be a back door... who knows?