If they didn't keep logs and aren't lying, they could still be asked or warranted to allow LEO to monitor their system live during a suspect's usage in order to identify them.
Regarding illegle activities, if there is a will strong enough that warrents Powers that be to track down something, one way or another, it will happen. No matter, how much one deludes himself into a sense of security. The idiot in the article shoudln't have been posting shit in a fucking irc channel to begin with.
Pardon my english, am very tired and not my mother-language.