My
#1 Rule of Choosing a PPC....
*** How does the PPC server handle 404 page requests from old links? ***
If they print "Not found" then I don't put expired traffic names there period.
When people talk of mysteriously doubling their traffic when switching to another PPC, it could be how the 404 requests are being handled.
Sedo (Not Sedo Pro) and Fabulous are unpredictable about 404 requests.
TrafficZ, DS and Goldkey are predictable. You should check it out with your PPC by typing random garbage image names into their sample page. This is how expired links will be handled. Do you really think "Not Found" or "Error" will get you any PPC sales?
2nd rule to choosing a PPC provider.
Do they allow good customization of the title,graphic and page?
TrafficZ takes top honors here. Massive number of configurations for a PPC provider.