What shopper in their right minds would order "Random Crap" from an etailer who describes the offering thusly:

Little do they know, when their packages arrive
They'll open them up and exclaim, "What's this jive?
"I thought I might get a giant-screen TV
Or at least a pair of sunglasses that play MP3s."
Instead they'll find garbage that the city dump
Rejected, so we sold it to you chumps.
And so we exclaim, to those let down by their loot:
"Merry Crapmas to all, and to all a crappy woot!"

Hordes of WOOTAHOLICS, that's who! I just made that word up, to refer to those crazed die-hard addicts of Woot.com who wait up til midnight every night to see what the next day's product is so they can order it before it sells out.

I am not a Wootaholic, but every once in a while around midnight CST I check what's on offer, and for the first time ever I saw the fabled "Bag of Crap" for sale!

I was SO EXCITED to see that fabled brown bag! Until... I noticed the SOLD OUT message. Damn!! Alas, I was too late.

ARRRRGGGGH!

Turns out the entire B.O.C. (affectionately referred to as "Blinged Out Cabbages" to the Wooter insiders) inventory of 3000 pieces was sold out in just ELEVEN MINUTES! Jeez, don't these Wootaholics have anything else to do on Christmas!?!? I wonder if I'm destined to ever lay my hands on a B.O.C.

Ah, to be an etailer like Woot who gets overwhelmed by frenzied mobs of shoppers on Christmas Day. That's brand devotion.

Discussion forums encourage customer participation, getting customers and prospects to stay longer which means more interaction with your brand. They drive repeat visits too. Some customers become "regulars" on your forums -- which should, hopefully, lead to you being top-of-mind more often when they are in the market for products that you sell. In other words, discussion forums make your site sticky. Not a bad thing!

Woot.com is a great example of an ecommerce site that encourages participation with forums. They consistently get dozens of comments per day; frequently it's even hundreds. For example, this blog post from a week ago generated 1200 comments in their forums! Their weekly contest is brilliant: they get customers to Photoshop images to a particular theme (which changes week by week) and then post their creations to the forums. Viewing the submissions is a lot of fun.

Online forums also generate wonderful search engine fodder. If the forum is architected correctly, each forum posting will become a separate page that ends up in Google, Yahoo, MSN, Ask, etc. And each of those pages will have been engineered to rank well (the HTML, the URLs, the anchor text of the back links, etc.).

We set up a forum for Van Dykes Furniture Restorers for their core customers (furniture restorers) to collaborate, share tips, ask and answer questions, etc. This user-contributed content is written in the language of the customers. For example, if a post is written about "gluing wood to metal" and that's the language that furniture restorers are using, rather than the product-focused industry lingo that the supplier is using, then that's new search engine visibility that hasn't been captured before by the online catalog. Multiply that effect out by the hundreds, thousands, or tens of thousands of forum posts and you've got the beginnings of a Long Tail search optimization strategy.