Friendly Botnet

I'm thinking of developing an application to be run on thousands of individual computers, in the background, a bit like a botnet, but a friendly version of a botnet. Each participant would accept to install a script on their machine, and they would know exactly what the script is doing - essentially information retrieval with a (distributed) web crawler to identify online fraud, browsing web sites and using text mining techniques to identify associations.

For instance, a user would have his/her machine check 200 web pages every day (in the background), and report statistics to us about the domains being visited. This information would be used to score domains, and eliminate fraud.

Are there any products currently offering this functionality?