I've been a member of all these PTC and PTR sites for a few months now. Thankfully thru the help of other bloggers and social network groups, I've weeded out the scam and lowrate sites from the legitimate sites that really pay.
Here are a few of the trusted sites on my list (there is more to follow as my list is growing)
Clixsense comes 1st on my rank. It offers many ads so you will make more as you click on them. It also pays you if you get referrals.
Follow this link to join for free: http://www.clixsense.com/?3474830
Wordlinx comes 2nd. It is similar to Clixsense: many ads and pay for referral. The point is the more ads it offers the more you make.
Follow this link to join for free: http://wordlinx.com/?r=371151
Matrixmails comes 3rd on my rank. Besides paying you to view ads and referral, it also pays you to read emails. How cool! Of course the email will have some ads in it.
Follow this link to join for free: http://www.matrixmails.com/?p=default&rid=29446
The last one on my rank is NeoBux. Despite nice graphic and layout, Neobux does not have many ads and it pays out less than other sites, average 0.5 cents per ads. But it still counts in my opinions. Also if you refer friends you can make more. Follow this link to join for free: http://www.neobux.com/ebookwagon
Also, here are some share-a-link related sites that you can earn from while sharing links on twitter or facebook:
Other growing social network sites:
Share Your Photos and Earn