Huge pyramid scheme, brah.
You promote their site, get points that you hope to redeem for something nice. But in all those people you invite, if even one is already a member or if one decides they do not want to use Lockerz, you are flagged as a cheater.
Site is largely glitchy and 'prizes' are redeemed within literally seconds. Meaning if you are not sitting next to you computer and know exactly when prizes go up, you have no chance.
And even if you do get lucky enough to redeem something, there is no guarantee you get it as they are prone to 'oversell' items.
Basically, you promote for them. They make money. They promise prizes, very few get them. The few that do make everyone else want them. Wash, rinse, repeat.