They are no longer working with respond.com infact their "split" was messy. I got an e-mail from respond offering to sign me up for free and transfer over my existing account credits. Then I got a letter US Postal from contractor.com stating as of some date they were splitting from respond.com then another letter stating something about litigation against respond.com blah blah blah.
Anyways I still get leads from contractor.com. I still use respond.com through Nate's site
www.contractorhunt.com which he set up looong ago.