Well the general tactic is that you will be given tonnes of ads initially then when you get really active they will reduce the number of ads all of sudden and force you to buy referrals to continue earning .... They also say that by upgrading you will get more ads .... So on and so forth ... Legit sites don't do that Smile
You're right, site like this is plusbux. they just have 4 ads for standard member, but have more than 10 ads for premium member.