Where I'm from, it's legal if you're making it for personal consumption but it's not legal to sell. You still need to apply for a license and pay taxes if you want to do that.
Since discussions tend to involve multiple people, wouldn't IPs need to be checked to insure that all participants are posting from countries where the activity being discussed is legal? So if three New Zealanders are participating in a discussion about methods of making moonshine then I assume that's OK from reading your post but what would happen if an American entered the thread? Would their posts get deleted?
EDIT: Also, it seems to contradict mrprep's post which suggests that any discussion about home distilling would not be allowed:
No, we dont have to check IPs as its really not that big of a deal.We dont have to monitor users, its on the individuals involved if they get caught doing something they shouldn't be. I'm pretty sure 99% of the time, something can be illegal in your country, but not illegal to discuss (as mprep said) the only time its really an issue are in sales threads, and even then its on the individual. If you buy some psychodelic blowfish that's illegal in your country, its not our responsibility to make sure that you did your due diligence. This is a global forum, rules and standards are different from country to country. Its not our job to enforce the thousand ridiculous rules of countries around the world.
I can assume from your comment that a informational neutral feedback (thus not affecting trust score) like the ones left over the MSDN Keys affair could be useful & helpful. e.g. I my country selling software keys outside official channels without COAs is a misdemeanor, or sometimes a felony, accordingly to IP protection law and other laws. Personally, I would like to save some bucks from keys but having to deal with courts & to pay advocates are too much to myself. So, I may put a neutral warning with references to remind users to check the relevant applicable laws before trading like this: Selling Keys from MSDN is not allowed as per Microsoft own TOS (see http://answers.microsoft.com/en-us/windows/forum/windows_7-windows_install/selling-product-key-from-msdntechnet-and-or/cf40c328-67ce-49b6-bbb6-c28cda92c06e) and may also be a misdemeanor or felony in your jurisdiction accordingly to IP protection law and/or other laws. This can apply also to Keys from other software houses. Always do your own due diligence before engaging in a trade!