It appears that this law could apply to people on a travel message board advising people where to take a ganja tour or anything about buying it...and that would apply to Amsterdam or anyplace it's legal as well.
The House Judiciary Committee passed a bill yesterday that would make it a federal crime for U.S. residents to discuss or plan activities on foreign soil that, if carried out in the U.S., would violate the Controlled Substances Act (CSA) -- even if the planned activities are legal in the countries where they're carried out. The new law, sponsored by Judiciary Committee Chairman Rep. Lamar Smith (R-Texas) allows prosecutors to bring conspiracy charges against anyone who discusses, plans or advises someone else to engage in any activity that violates the CSA, the massive federal law that prohibits drugs like marijuana and strictly regulates prescription medication.
More: http://www.huffingtonpost.com/2011/10/06/us-drug-policy-war-congress_n_998993.html?ir=Crime
One wonders why Republican Rep. Lamar Smith feels that his time is better spent on this nonsense than on dealing with our economy and other issues....