Adsense changes their referrals from 90 to 180 days in order for you to earn from them. As much as I wanted to become a referrer, I doubt many publishers can go past their minimum earnings limit. Hell, even if they make it a year, I still doubt beginners can achieve that. And almost everybody who’s a popular blog is already signed up. I only have one word for this, I-dont-care. Hardly.