I agree on a moratorium: 3 months seem ok to me; 1 month is a bit short. (Make it months from the day of posting - there will always be some who inadvertently mess up counts by a day or two...)
I believe any new rules should apply to all EAAF fora - fishing for information to promote sales is not limited to keris and I believe the same standards should apply to the whole community here. (I believe this has been the intention in setting up and maintaining this wonderful resource - please correct me if I got it wrong, Lee!)
As already pointed out, it's fairly easy to spot repeated commercial behavior on this site; however, I'd be more concerned with info gained here and (ab)used elsewhere (ebay, etc.). Thus, if any info gained here were to be utilized freely elsewhere, I'd still need to frame my answers here on the forum accordingly (not different from the current situation). IMHO the moratorium should apply to all venues. We would certainly miss some offending sales; however, I'm confident that repeated offenders will get caught by the community.
I'm not yet sure how to deal with honest change-of-heart situations as pointed out by Detlef. There are also newbies who would like to get info on inherited pieces or souvenirs. Some realize that collecting is not their thing and decide to sell off the piece under discussion (many just prefer a little cash or want to get rid of the tourist trinket but there are also those who realize that a valued family heirloom may be better cared for in a specialized collection and may even aid research). I'm not convinced that imposing the moratorium in those cases would be sensible.
How about another subforum dedicated to identification of unknown, weird, and possibly-for-sale pieces? Comments in such a subforum could be considered free to utilize for possible future sale and answers framed accordingly by those choosing to give advice. I could also envision that threads posted in any of the other fora could be moved to this special "quarantine section" once the thread starter has acquired permission from all contributors. Moreover, it would seem suitable to me to be able to move an identification thread over to the swap forum (shouldn't be noticeably more work for the moderators, I guess). This would also allow an exclusive offering in the swap forum before a seller decides to move on to other venues (if such a separate - possibly 1 week - moratorium is deemed preferable). IMHO it should also be possible to move an identification thread over to the more pertinent subforum if the owner decides to keep it in his collection (for the next 3 months) and would like to get more detailed discussion.
In short: In-depth discussion of pieces deemed to stay in the own collection in the major subfora (Ethnographic Weapons, Keris Warung Kopi, European Armoury), offers and trades in the Swap Forum, and a flexible Identification Resource to fill the gap in between.
BTW, I still feel that keris sundang (Moro kris) and tombak (and rencong, and badek, etc.) should be an integral part of the Keris Warung Kopi. Arguably, it would make much more sense to include all stuff from the SEA archipelago (Malay culture in a very wide sense) here. Yeah, just nagging...