If you want to earn online for paid to click, first you should know if the site is scam or not because scam sites donnot pay you anything. Following are tips to find those scam sites:
1. They Giving away high payment per click.
2. They dont have forum or comment type anything where you can ask/share questions/information.
3. They are displaying paid lots of dollars.
4. Repeatedly mentioning the same facts.
5. Very high payout limit.
6. Mostly do not use paypal option (rarely)
So here are the sites which are not scams i think.
1. They pays low rates per click (0.01$ or less)
2. They have their own forum (with active admin)
3. Low payout limit.
4. Use paypal / Alertpay as payment option.
What other things do you think matters ? Please list them down so that not many people are fooled by those cheap scam sites.