There are lots of ways to earn on internet. But the most effective way that I have seen is Ziddu.
Ziddu is a free hosting site for your file hosting and they offer you some earning when your file is downloaded uniquely. The term is unique. It means that file should be downloaded from a different IP address as well as the file should be different in case it is downloaded by the same IP address user.
They also offer referral earnings and believe me they offer really good money.
To join ziddu click the banner below.