Compliments of Lifehacker.
Are you're tired of seeing duplicate product search results in Google from the likes of eBay, Bizrate, Pricerunner, and Shopping.com? The hard way to clear them out is by stacking up the -site:ebay.com -site:bizrate.com -site:shopping.com operator in your search.
However, Lifehacker shows a better way. Just use the GiveMeBackMyGoogle website to do your searching and get clean results instead of the usual clutter that Google returns.
Here's an example.
Search for a Cruzer 1GB flash drive at GMBMG and then compare the results with a regular Google search.