From which countries accounts like you will provide? is it any auto like system?
He's probably doing it manually, I think he has same password to all accounts and repeat log in/ log out session + liking with a macro recorder. That is possible, I'm doing it in excel too when I gather emails
Lol. Are you kidding? Don't you think that will take forever to do 3500 of such task? Who would do that much trouble for $0.3 knowing that you have to do it 3500 times. There are lots of autolikers out there if you spend enough time to search for one. And also if OP has 3500 accounts in facebook, he should've also make a service Facebook's Fan Page Like since he is the owner of that 3500 accounts. But he did not, obviously because those 3500 does not belong to him but it's from people who've subscribed to a social panel or an autolike service.
. It was just first attempt so i'm not sure what is the range of this service. 