On the Internet, is it OK to have anonymous pamphleteers?

Here's a good example of direct-to-consumer political messaging that is
potentially untrustworthy because it is unsourced.  It raises the question: Is it OK for political speech to be anonymous? 

Tonight I go to DailyKos and find a banner ad across the top, obviously
geocoded to Massachusetts, about a hot political issue in the Massachusetts Legislature -- a bill which would require automobile
manufacturers to make public electronic testing codes for their "black
boxes" so that repairs could be made by anyone, not just authorized
dealers and repair shops that spend a lot of money on special equipment
from the manufacturers.

So the clickthrough goes here:
http://www.nomassr2r.org/

But **nowhere** in the text on that page is there any indication of who is behind the website. Only by clicking on one of the links, did I figure it
it. The link went to a QuickTime audio of a 30-second advocacy radio spot, which ends with: "Paid for by the Alliance of Automobile Manufacturers."

Now from that one can assume -- but can't know for sure -- that the website NoMassR2R.org is also a creation of the Alliance for Automobile Manufacturers. As a consumer I need to know this in order to assess the message as an argument in favor of  the auto manufacturers' position -- they want to keep control of their testing codes and make money selling expensive equipment to read them.  For the radio ad, because of FCC rules, they have to identify who paid for the ad, because it has a political message.

So, on the regulated airwaves, you can't be an anonymous political
pamphleteer. But on the web, you can.  Is that good, or bad?