Now, he's added that he would like to see marketers get Web users' express consent before tracking them online in order to serve targeted ads. "Opt-out isn't illegal necessarily, but I think the better practice is opt-in," he said this weekend in an interview that aired on C-SPAN.

Leibowitz was speaking about Internet privacy and the importance of obtaining consumers' consent before using their data, when interviewer Grant Gross of IDG interjected that many companies allowed users to opt out of online tracking, but didn't first seek their permission.

"I think some of the more enlightened companies do do opt-in. I think a lot of them don't," Leibowitz responded. "I think the better practice is always opt in."

Now, expressing a preference for opt-in consent is a far cry from mandating it, but behavioral targeting companies still should take note that a top regulator is publicly urging them to move away from an opt-out standard.

The remarks are especially striking because industry groups have generally said repeatedly that companies engaging in "anonymous" tracking and targeting should notify users and let them opt out.

Leibowitz's views notwithstanding, it seems unlikely that behavioral targeting executives will embrace an opt-in standard. Much of that position is driven by the belief that people don't tinker with default settings and, therefore, will not opt in to targeting.

But even if that's currently the case, one reason why people aren't currently changing defaults surely stems from the fact that to do so often requires deciphering long and dense privacy policies. Perhaps people would read policies -- and change their settings -- if the documents were easier to understand. In fact, even without moving to an opt-out standard, notifying users in clear, simple language could probably go a long way towards addressing regulators' concerns.

This commentary is insightful. I recommend it to others.