I'm a lurker of Bitcointalk but I saw this and felt a lot of new people would get scammed by searching google for a referral link, the best place I found is Reddit. They themselves promote only one link to claim all the referred people come from them (The Agora Reddit Staff ARE NOT the Actual Agora Staff), but a user posted this a while back and this is what I used to register, so far so good!

You folks can checkout this link:

http://www.reddit.com/r/AgMarketplace/related/22b748/verified_agora_referral_link_you_can/

All you have to do is double-check the PRIMARY URL against the established URL on the right side of the Reddit, and you should be good to go! Also, after registering establish PGP Encryption Logins, and you should be rock-solid.