Using the pre-qaul tools on lender pages does not affect your credit score. They can sometimes give you targeted or better offers for a credit card than on the general listing. Getting a response also does not garuntee approval and if you do apply even through a pre-qual page does result in a hard pull.
No impact whatsoever to use Cap One pre qual site, also over the last 2 years I have been approved for 6 Cap One Accts and 3 times the system did not pre qualify me. I applied anyway and all went well.
