DP have the best opportunity to earn Check out content creation section and don't waste your time on clicking those PTC sites that mostly are scam
If you are skilled in English, an extremely easy thing to do is content creation, as milamber said. If not, I'd go with data entry - It's not too hard to find a data entry job that pays >$10 per hour.
There is no best way to earn money on the Internet. It all depends on what skills you have and what skills the Internet demands at this moment.
As suggested above it all depends on your skills. If you can write well then you can earn from content creation services or you can open your own blog and introduce some ads which can fetch you some $$$. If you have good gfx skills then you can design logo's or banners and can sell them at contest section. You can even start off with some sites like imagehosting, forums, blogs etc and can earn from them by placing ads. Hope this helps you Best of luck!
I suggest more for him to get a blog.. A forum isn't that easy to handle.. And image hosting needs more advertising to be popular. But when blog, you can get backlinks on forum signatures which is cheap! Or be tricky to advertise your sites/blog(s). Goodluck
what ever you do you need to find something that interests you or you will quickly find that your effort becomes work.
depends on the skills of the person On DP intself, you may see a numbr of oppurtunities in the Business section