Deadly serious. See the key policies at https://en.wikipedia.org/wiki/Wikipedia:Verifiability and https://en.wikipedia.org/wiki/Wikipedia:Reliable_sources
I revert crap that fails these tests all the time - mostly bored schoolkids and political nationalists, with a fair scatter of nutters. Looking up your own sources so you don't get the same treatment is a stunningly effective way to educate yourself and have a blast at the same time.
Note too that while Wikipedia does not regard itself as a reliable source, its articles on mainline topics contain fewer errors than the Encyclopedia Britannica.
Biting the hand that feeds IT
