[Larwee]

Google says the following:

If you're outside of North America, Latin America, and Japan, AdSense referrals will be retired.

Google also said this:

If you're in North America, Latin America, or Japan, the pricing structure for AdSense referrals is changing.

Here are those details:

About a year ago, as an experiment, we changed the pricing structure for AdSense referrals so that when a user you referred to the program earned $5 within 180 days of sign-up, you would also earn $5. When that publisher earned $100 within 180 days and removed all payment holds, you'd receive $250. We have decided to conclude this experiment and return to the original pricing structure. As a result, we'll soon no longer be offering the $5 bonus or $2000 bonus, and the payout for referring a user who generates $100 with AdSense in the first 180 days will return to $100.

These pricing changes will take place during the last week of January. A referred user who reaches $100 within 180 days of signing up and who removes all payments holds before the change occurs will generate earnings of $250 for the referring publisher. Any referred user who meets this conversion criteria after the change occurs will only generate $100 in earnings for the referring publisher. In addition, the $5 bonus will be removed at that time. Please note that the date a user was referred will only affect where the 180-day window is set but not necessarily the payout the referring publisher receives. For example, it's possible that a user referred in early January will meet the conversion criteria before a user referred in early November, and so the resulting payout may differ.

If you would like the full story, here is an official Google link where you can get all of the information about this Inside AdSense: Upcoming referrals changes