After updating the Adsense Policies, now Google updates its pricing structure for Adsense and Adword referrals. It’s posted at the Adsense blog.
For AdSense Referrals, it said:

* When a publisher who signed up for Google AdSense through your referral earns their first $5 within 180 days of sign-up, you will be credited with $5.
* When that same publisher earns $100 within 180 days of sign-up and is eligible for payment, you will be credited with an additional $250.
* If, in any 180-day period, you refer 25 publishers who each earn more than $100 within 180 days of their respective sign-ups and are all eligible for payout, you will be awarded a $2,000 bonus (bonus payouts are limited to 1 per year).

With this new pricing structure, I think, it will be hard now for me to earn the promised $100 referral earning when my referred Adsense Publishers earn their first $100. To let you know, I have referred more or less 100 new Adsens Publishers according to the stats out of the thousands of users who was referred to but didn’t signed-up accounts.

I think, it is impossible for me to earn this now, except if a webmaster who owns a high traffic sites signed-up Adsense and Adwords through my referral program.

However, I still have a chance to earn the $500 referral fee as stated:

These rules will also apply to users that you have already referred but who have not yet reached one of the new earning/spend thresholds. For example, if you referred an AdSense publisher who has currently earned $2.00, you will be paid $5.00 if that publisher reaches the $5.00 mark.

But then those Publishers who came from my referral and earned more than $5 already can’t share something anymore for me, except if their earnings reach $100 mark within 180 days, which I think still blur to my sights.

But, if you have referred an AdSense publisher who has already earned $10.00, you will not be paid $5.00 retroactively for that referral reaching the $5.00 mark. However, should that publisher eventually reach the $100.00 earnings mark within 180 days, you will be paid $250.00.

Updates (February 3, 2007)

I think I was misinformed about the previous Adsense referral payment structure. I thought I will earn $100 if the publisher from my referrals earned his first $100 in any days since he signed-up the program.

ProBlogger Darren made me realize this:

When a user you’ve referred to AdSense first earns US$100 within 180 days, AdSense credits your account with US$100.

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