There is the case of Sherman Austin, who was convicted in the U.S. for
posting bombmaking information on the web. The law in question is not
some post-9/11 Republican thing, it's a 1997 law championed by Dianne
Feinstein (D-Calif) and signed into law by then-President Bill
Clinton.
Mr. Austin pled guilty rather than fighting it, which may or may not
have been a sensible thing to do under the circumstances. (I tend to
think that it was not a sensible thing to do, but I'm not in a
position to judge.)
It is unclear to me whether such a law would be upheld as being
constitutional, because the law requires an element of criminal
intent, that is, it is illegal to post information about bombmaking to
the Internet _with the intent that readers commit a Federal crime of
violence_. In a recent case, the Supreme Court upheld a law against
burning a cross _with the intent to intimidate_.
In any event, such a law would clearly not apply to Wikipedia, because
our intent would never be that people commit crimes of violence. At
the same time, of course, I would find it extremely unpleasant to be
faced with a bogus prosecution for such a thing. I have a little girl
at home, and I don't intend _at this point in my life_ to sit in
Federal prison to make a point about freedom of speech. (I very much
respect people who would, though, if their life circumstances are
appropriate.)
--Jimbo