Not only signature campaign alone will give you bitcoin for that you have to be high rank , but apart from that you can do lot of skill work in the service section where you can get the job for bitcoin, and in altcoin section you can earn through so many new coin giveaways and some doing small work and you can earn free coins and then you can sell them and earn bitcoin when they hit the exchanges. and if you are lucky and that altcoin runs profitable that day will be a lottery winner day.