Answer is advertisers like small business owners are advertise their websites or their business on these sites like clixsense, neobux or any ptc. so these sites are pay to the members who view those websites
The secret of success by earning money with clixsense is referrals join by you. Your earnings without referrals is go slow but with incresing referrals your earnings also increase likea mountain.
Ways to get referrals :
You can earn money by following steps: