Google and Yahoo are exemples of search engines. But in these two sites you don't earn anything when you do searches.

However there are other sites with search engines where we can earn some money. The scheme is as follow: you open an account in the search engine website and then you use the generated HTML code (on your web pages) or redirect your trafic to the portal and everytime a person does a valid search (search and click in a result link) your account are credited some amount of money.

It is with the usage of this scheme that the majority of PTR(paid to read) sites earn money. If you don't have a PTR site, or if your websites has little traffic you still can earn money with search engines. I just need to buy advertisements in PTR site and wait that their users do valid searches in your search engine portal. See here the best PTR sites where you can buy visitors.

In PTC sites you can also earn money from your downline.

These are the best search engines sites in the market, and the one that I use in my own PTR: