Since about a year ago AdSense referrals earned you $5 within 180 days of sign-up if the person you signed up generated at least $5. When that publisher earned $100 within 180 days you’d receive $250. Lots of blogs, small business and even some high traffic sites have been displaying these badges for years now and have been making a lot of money from them too. But now Google has decided to kill the referrals program because it “has not performed as well as we had hoped”. Well, except in North America, Latin America, and Japan.
You will still be able to generate referrals for other Google products, just not for Adsense. You may want to replace any existing referrals promoting AdSense with referrals because “any conversions which occur after this change is made will not be recorded in your account.”.