Actually it goes back to MLParena. Your not far off though. If I remember corectly it was April 1st and the mods played a joke on everyone. Via the censoring of words. So, if you said little it would replace it with moldy. Then pony would be replaced with fart. This had to of been 2011 or so.
My name used to be Saphtalon and then changed it to Abbaheart. After a while new websites like Derpibooru popped up. I was an idiot teenager and I owe it to the moderators of MLParena for my maturity. I joined that forum around 2008 roughly.