Bribery doesn't always work

At least not if you're competing with Google for search. [Link]

Way back in 2005, Bill Gates suggested that in the end, Microsoft would be able to beat Google because it had a secret weapon: it could bribe users to use Microsoft instead of Google, by offering them a cut of the advertising revenue. It took a few years, but Microsoft finally turned on that "feature" on a limited basis in 2008, offering cashback for people who bought certain products after searching for them via Microsoft's search engine. Later that year, it expanded the program to regular search. What happened? Not that many people cared enough. Microsoft kept upping the ante, but most people didn't care. They were happy with their Google searches, and even if Microsoft was paying them to use its search engine, it wasn't enough. Well, except for people who figured out how to game the system. But that's not who Microsoft was targeting.

Bribery like this only works if you can bribe one person who can make others take the sub optimal choice.

In effect, if you have to pay people to use your system instead of the better free alternative you're doing something wrong.