An increasing number of postings on the Design and Construction Network's discussion group are selling messages. If groups allow too many of these to dominate the board, real discussion dries up, and the group loses its relevance.
One of the great challenges in the online world is that access is both free and easy. This means the conventional barriers to the wide distribution of mediocrity or irritation are greatly reduced, so much that appears on line is less than inspired.
We build our own filters to keep this junk out of our lives. Spamblocks stop much of the stuff, and our common sense causes us to quickly hit "delete" to the garbage that still gets through.
Online forums and newsgroups have similar challenges. There appears to be a critical mass beyond which things go really wrong, unless you build in some seemingly heavy-handed controls.
With too little traffic and engagement, there isn't enough critical mass to create dialogue, conversation and real online communities. But after a certain threshold occurs, the spammers and (for want of a better word) proto-spammers take over.
Spammers produce the obvious garbage, with auto-generated crap spewed out in huge volume with the hope that only a little will stick.
Proto-spammers are spammers at heart, without the volume. They are generally not-very-good salespeople, who think that putting out a "free advertisement" (sometimes thinly disguised as an information article) will produce useful results. Just like spam, or irritating telemarketing, or annoying canvassers knocking on doors, a certain number will respond to "selling" posts so, if you do it often enough, you may get some return.
Trouble is, as soon as that type of posting takes over the online forum or group, regular readers who might actually can buy something, usually run for the hills, and the group dies a painful death.
How do you solve this problem? I see two possible solutions.
Set moderators and rules. You need people to stand guard and keep the crap out. Volunteers can develop a code of conduct, a set of rules, and guidelines. If something is wrong, they can kill it. In some cases, they have their own private closed forums to discuss sensitive issues. In large sites, you can even build in an appeal/review process, to allow people who may be inadvertently (or maliciously) screened out a second chance.
Charge a (small) fee. In some cases, the best way to impose the discipline is to charge a small fee. Craigs List is an example. It is the absolutely most effective place to advertise help wanted offers in cities where it charges a small fee. The $25.00 is far less expensive than the conventional job board fees of several hundred dollars, and the quality of responses is excellent. Without the fee, however, multi-level marketers, "home business opportunities" and other scams and dubious employment offers drive out anyone who would actually be interested in a real employment opportunity (or offering one).