Hayri, to be eligible to have an AdSense account through this site, you have to fulfill some criteria.
1. You have to be active here for at least 6 months.
2. You should have updated your address and info about you on this site.
3. You should have written some good quality articles, minimum 10.
4. You should have achieved Gold level here.
5. You should have received at least one prize/award.
6. you should have uploaded your profile pic.
You have to fulfill all these criteria to have an adsense account. Even fulfilling 5 out of the above 6 can be regarded sufficient to have an AdSense account through this site.
Else if you are having your own existing AdSense account, you can associate it here anytime.