@Tab LeTrivia: 9/23/2013 - https://www.warzone.com/blog/index.php/2013/09/
Or 9/22/2013, depending on your time zone. Technically REGL (first "official" clan) were founded 9/22/2013 going by US Eastern time: https://www.warzone.com/Clans/?ID=1
I joined in 2013, a month before the clans update, and even then my account is too young to remember the last time Pulsey was relevant. So I think his definition of old is like 2011/12 or earlier.