Yahoo has just announced on it's Search Marketing Blog a new desktop tool to administer PPC marketing on the Yahoo PPC marketing networks. I've not really used yahoo PPC much, but in past experiments, the cost per conversion for yahoo online marketing is about the same, if not higher than adwords. The situation might have changed in the past couple of years, and with the addition of a desktop marketing tool, it might be easier to administer your campaigns and try to tweak them for the optimum cost per conversion ratio. One case study on the Yahoo advertising site claims to have reduced workload on managing PPC campaigns by a factor of 10.

I've seen a few third party apps out there for google PPC management, however google itself has not really offered a desktop management tool that can be used offline to update campaigns then publish online. Since the chrome OS will be focussed on cloud computing, it is unlikely that google will be issuing such a tool in the near future.