Although Google TV Ads continues to chug along, ignoring the accumulated uncertainty on the part of media execs, there are a few reasons why the service’s future has drawn more questions. The advertising industry is barely set to recover from two terrible years of depressed ad spending. While advertisers are attracted to the promise of greater targetability that Google TV Ads offers, they’re also loathe to spend a great deal of money on a service that has very little scale and continues to appear a little too much like an experiment.

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Secondly, there has been some notable retrenchment among other high profile addressable TV initiatives. For example, last June the cable industry-backed Canoe Ventures put its anticipated ad targeting project on hold after conceding that the limited technology of some local cable systems made a rollout of the system impossible.

Google’s own actions have contributed to the lack of confidence. In early ‘09, Google closed down its radio and newspaper ad serving efforts after months of promises to revolutionize the way media was bought and sold across those segments. Then, last spring, Google TV Ads said it would extend its auction system to include full-length broadband TV programming to websites beyond Google’s YouTube.

Mike Steib, Google’s director, emerging platforms and TV ads, has heard all the doubts before, telling Mediaweek that “Google has the stomach for this…if we’re not adding value, they’d pull the plug.”

Aside from the wariness being expressed by media buyers like SMG’s Scheppach, the weak economic recovery—along with Google’s many other challenges from China to Microsoft’s Bing—there’s no reason to think that the service will remain all but limited for the rest of this year.