In a case of first impression, the Ninth Circuit holds here that the government is permitted to tap into your computer and record (1) the IP addresses of all the web sites you visit, and (2) all of the e-mail addresses to whom you send and receive e-mail. Without probable cause. Or, presumably, any reason whatsoever. As, according to the Ninth Circuit, obtaining that information isn't even a "search" under the Fourth Amendment.
I think that's scary. It's not the kind of intrusion I think most people would expect the government to be able to perform merely on a whim.
I admittedly understand the seemingly facile analogies that lead Judge Fisher to conclude that this is okay. He thinks that recording IP addresses is no different than recording phone numbers -- an act that the Supreme Court held (in a 6-3 opinion back in 1979) doesn't constitute a search. And he concludes that recording all your e-mail addresses isn't any different than recording the addresses that are printed on the outside of your snail mail, which isn't a search either.
But, in my view, these things are different. Even if a pen register isn't a search (and I think that the dissent in Smith back in 1979 made a pretty good argument to the contrary), obtaining a list of all the IP addresses that someone visites gives you a lot more information than merely recording telephone numbers. So the privacy invasion -- and potential for abuse -- is manifestly larger. And my view is that footnote 6 of the Ninth Circuit's opinion, in which Judge Fisher says that recording the actual URLs perhaps might be a search, is a distinction without a difference. Once the government records that I'm going to the IP addresses for NAMBLA and High Times and Bondage.com, the fact that they won't (initially) know which particular page of those sites I choose to view hardly matters. They've already invaded my privacy, and know a boatload about me that I'd rather not reveal to the government, TYVM. And, yes, in theory, e-mail addresses arguabley might be seen as the same as addresses on a snail mail envelope. But they're viewed as more private, and rightly so, and I think the Fourth Amendment shouldn't be (and isn't) blind to that reality.
I'm sure there are some people out there who'd be happy for every single IP address they ever visit to be instantly captured by the government and broadcast to the public. But I'm fairly confident that lots of other people wouldn't be similarly thrilled. And by holding that capturing IP and e-mail addresses aren't a search, I think the Ninth Circuit's decision here is extremely dangerous. And, in my view, wrong.