Wrong. You post on the internet (or even visit many web sites) they record your IP address. An aggrieved or offended party (including your employer) applies to an appropriate Court for an Order requiring the site publisher to release the IP address and your ISP to release your name and address. It has happened a number of times over the years with PPRuNe.
Well as long as you are using your own computer, using multiple internet cafe's will provide multiple IP addresses, and if you are in Iceland, well they are about to become a haven for internet freedom including anti-libel laws so I guess Wrong! is not the right word, depends where you are! In Iceland you will be able to bag everyone and every company with impunity! Go for it! and show these internet nazis the way!
There are already pseudo firewall softwares routing your IP address so I guess it comes down to how much you know about the net hehe!