They do not send checks out automatically. Users do have to request them. They have paid their members, so there is no worry that they will not pay. You may only sign up with one account per person. They do allow up to 4 accounts per household which, in my opinion, is a major perk.
Membership is limited to the U.S. and Canada.
This cuts down on the number of referrals one can acquire. I would recommend this to someone who has spare time on their hands, and is looking to make some extra change. The search engine does not come up with near the number of results that others do. I would not recommend this to those who are only interested in doing research.