PRR - I think you miss my point entirely. I'm not suggesting that a mechanism be developed for judging the value of members!
This is about sellers in the BM having a tool to use that can allow them to sell comfortably, without having to jump through the usual hoops that one does in order to avoid getting ripped off. It would be up to the individual to determine whether or not they think it is useful to engage filters. Remember, as it stands, Ethan has set up the BM as an auction with a commitment to sell. That's quite different from a classified-style listing where you can feel free to accept or reject an offer to buy.
What is one to do when the buyer joined today and has zero posts? If I'm selling a lock washer that I've put in an envelope, then I'm out less than a buck, and I'll take the risk. On the other hand, if I'm selling something for $5k and putting up $150 for shipping on top, I'm gonna want some assurance that things are going to work out OK. That's where things get tricky.
As I said previously, I would choose to sell on the BM instead of eBay primarily for two reasons:
1) I'd like to offer my surplus gear preferentially to forum members
2) I'd like to do a simple, hassle-free transaction
If I'm selling to you (PRR), or any of the core members, then I won't give it a second thought when I box up my $5k whatever and front the postage. You say the checks in the mail? Fine. I'm not willing to go that far for anyone who can use a search engine to locate my listing and join the forum.
It's all a matter of what one feels defines a community. For me, participation and longevity are big factors, especially where trust is involved. I absolutely agree that a new member can hit one out of the park on their first post and make themselves a valuable community member right away. On the other hand, smart and valuable contributions do not equate to, or establish, trustworthiness.
I think it's important to remember that the new BM is for single items, and comes with a binding commitment to sell, while the new FM is the place for group buys (sellers/organizers take some risk here, but it is minimal, because it is unlikely that large numbers of members will fail to honor their commitment), and then the WM is place for business transactions, which are usually credit card based and have the usual mechanisms for recourse when a transaction goes bad.
Why should I care to comment at length here?
I think that it is justified because the BM is a pay-to-play device and I have some notion about what I want out of that deal.
Do we need all of these markets?
No! It is a convenience, but these functions can be handled off-forum. On other forums (fora?) people have personal and commercial items for sale with links in their signature line. No discussion of sales in the threads. Not my favorite style, but it's an option.
Will some new and trustworthy members be excluded?
Sure! But, who cares? They have no pressing need to buy, and I have no pressing need to sell. Should either party have such a need, they should probably be in the WM.