The world’s largest online poker site is set to make a drastic – and retroactively applicable – change to its affiliate program. That’s per an email from PokerStars to affiliates (included in full below) announcing that as of June 1st, revenue share will only be paid on referred players for the first two years of the player’s activity. The previous terms saw affiliates credited with revenue share for the lifetime of the player. The change applies to new and existing referrals. The upshot: Affiliates will no longer be paid revenue share for any player referred before June 1, 2013. It’s…