Making it viral

I don't work on the American Facebook, only in the European one, but here, Facebook is really under-explored. So I made some pages go viral, but I spent about 500$ on ads.

I wanted to know how could I make them go viral, using a software or any codes.

What about facewizard, etc?

Can you help me?

Thank you very much

Also, make sure you are sending quality invites, not overseas users in third world countries or people who only login to FB to play Mafia Wars and/or FarmVille, etc.

you can only invite 50 a day to a new group?

Not 50 a day, 50 at a time if you want the invites to actually go out. I know this is the case for fan pages, and I am pretty sure it is the case for groups as well. Even if you select more than 50 friends and send out the invitations, FB will say they were sent out when in all actuality they were not. To play it safe, you might only want to invite 45-49 at a time, and keep it random in between those numbers.