Money, yes that's the reason why i'm learning internet marketing, there's many ways to earn money from internet:
1. As a publisher there's google adsense or similar programs that will give you money from ads you publish at your blog/site
2. Or you can sell product such as e-book or software
3. Affiliates, join this programs if you dont have product to sell, affiliate will provide you products all you have to do is sell their product
4. Click for money, yes that's right, all you have to do is click ads or submit for product review and earn money
simple.