Do ad blocking plugins cause copyright and terms of use problems?

CNet News has run this interesting article which raises questions about whether ad blocking software may face legal challenges from website publishers and advertising providers. What we’re talking about here are browser plugins that the user chooses to install, that allow web pages to be viewed sans the advertisements. Website publishers that rely on ad revenue (as well as upstream providers of advertising services, read: Google) may be concerned about such practices for obvious reasons.

The article speculates that if this kind of software were to face legal scrutiny, the plaintiffs would argue copyright infringement and violation of the sites’ terms of service, which may prohibit the use of this kind of software.

But who exactly would the plaintiffs sue? The individual users? The makers of the software? Maybe both, and depending on the defendant, the theories may be different.

Going after millions of users would seem impracticable, and the damages calculations in each of those situations would be problematic. What we could see, if we see anything at all on the lawsuit front, are challenges against the makers of these browser plugins.

This will require some creative theory-making. It does not seem like the software providers are the ones doing the actual “infringing” (i.e., aren’t the ones changing the appearance of a page thereby making an unauthorized derivative work). So I suppose the advertising side would put forward some type of inducement theory of secondary copyright infringement liability. Grokster will come in handy in those cases. And for the breach of contract aspect, perhaps we’ll see theories of tortious interference.

Maybe it’s a tempest in a teapot, and nothing will happen. But there could be a lot of money at stake, and that aspect could provide a strong catalyst. On the other hand, doesn’t it seem like the individual user has a clear right to determine what content is delivered?