Internet Law?

I have a friend that likes to explore and take photos of modern and decaying urban infrastructure.
He discusses his explorations and organizes outings on a forum.
Now the thing is, there is a $20, 000 fine if he gets caught when he's out poking around in underground pipes and long-abandoned carparks.
So I'm just wondering, is discussing and making plans to do these illegal things illegal to do on the internet? Can the police shut the site down?
Because child pornography is illegal, and those sorts of sites are shut down all the time, but at the same time there would be millions of sites out there demonstrating and giving instructions on how to do a whole range of highly illegal things. So is it an issue of manpower, and the most illegal sites are dealt with? Because it seems illogical to just shut down some sites but not others.

I just started wondering about this today, and there really doesn't seem all that much information about it on the net.
We have laws governing everything we do every day, down to the point of dictating whether the individual can smoke or not as they're strolling to work, but the fastest growing media and form of communication that has ever existed has only the barest of legal frameworks holding it up . . . or limiting its growth, as you may.

It's a topic that will no doubt gain much more attention as time progresses and the internet becomes the primary means by which people communicate, work, learn and trade, (read; LIVE) but there seems to be bugger all about it anywhere.

Conspiracy is conspiracy, regardless of the medium. If both parties (maybe just one, depending on your local laws) are in the US, then the internet is no different to a phone call or a meeting in a pub. Now if the website is hosted in the US but neither party to the conspiracy is a resident, that's a bit more dicey. In the case where a bunch of US citizens conspire to break the law online, it's open and shut. Tell your friend to make sure his site is secure. Only allow people he's vetted personally access to it and make sure the front page seen by people who aren't logged in has nothing to do with breaking the law. If he wants advise on how to do this, get in touch with me.