Yahoo! to conquer the market and to reach as google search engine, pays to do your research.
You are paid a few cents of pound for every search you make, you are also paid for the researche of the friend you invite.
If you sign up with a link of a friend you earn 5% more 'on your research.
To reach the site, join as my friend (and therefore the 5% more 'gain on your research) or read the rule, click [Only registered and activated users can see links. ].