Yes. It's also old news. The new news here is that FBI used regular warrants to infect everyone who visited a certain website with malware, which I think is inexcusable under the 4th amendment - and common sense.
Highly debatable. As pointed out in the comments of the article, the FBI would not require a special warrant to watch people going in and out of a crack house.
But this isn't watching them going in and out of a crack house. This is watching all their movements after going in and out of a crack house. Still debatable, but I think your analogy didn't show how broad the scope of this would be.
and possibly after pulling into the driveway of a crackhouse for a three-point turnaround.
If visiting the site itself is prima facie evidence of wrongdoing -- like child porn -- I disagree. In the case Silk Road, I agree: users could merely be motivated by curiosity and therefore browsing isn't on its face a crime.
What about misspelled domains? DNS Hijacking or Bit Errors? Hostile redirects from innocuous hacked domains? I'm not against using access as evidence, but there needs to be more context than a single attempt to access a domain.