Well, I'm not sure of the date, but I do remember when I came back on one day and it was suddenly full of ad's. I'll admit I was here a lot more when it was ad free; however I also don't pay the bills.
Otherwise I'd say 25 August 2013, the day I realized this place was still around. I'll be firing up an IRC client shortly to test that out.
Knowledge first, World Domination second