Although a total of six broadband providers tested the system, none were still using it as of last month. It's hard to see what choice NebuAd had other than to admit it was no longer deploying ISP-based targeting strategies.
The news came after months of condemnation by advocates and, in some cases, lawmakers. Certainly the pressure seems to have played a role in the ISPs' decision to stop the tests.
But there are also questions about whether, even in the absence of political pressure, the companies would have decided the platform made sense. Without knowing the results of the tests, it's hard to say whether NebuAd was able to turn a profit after paying the ISPs for data and Web publishers for ad inventory. And it's also hard to know whether the targeting was in any way effective.
Figuring out return on investment is always difficult, but some people have wondered for a while now whether behavioral targeting works -- or at least whether it works well enough to ask consumers to give up some privacy in return for targeted ads. Even without NebuAd's ISP-based targeting programs, that question remains.