Just a couple of notes in regards to the points that Chip brings up:
Facebook page
It certainly has its limits. I don't even attempt to post all the info, just a teaser usually the title and subtitle of the item (most is caught by the auto-posting link available on each ad's page), and maybe some other info (e.g., price) thrown in. It's all manual (ugh!) and not sortable, just a jumble. A facebook page doesn't make a good database. Granted I haven't even attempted to keep up with the ads that are taken down for whatever reason (sold, etc). BUT, if somebody's following GS on Facebook they can get an advisory when I post something new, and maybe they'll come and check it out.

Technology for technology sake.
The technology I use is a tool to provide the functions that I wanted. User friendly self posting and edit, automatic photo resizing, displaying the number of ads in each category, contact/messaging feature, detailed hit counters, anti-spam, video embedding, sorting, searching, building that cool google map (ok, I did that one just for fun), and management of the site with minimal manual daily work. It's like being on autopilot. It does everything pretty much automatically, I just have to monitor it, talk on the radio, and tweak the heading knob every once in a while.

RSS Feed
I know most people don't know what that its. That's OK. But it is another way for folks to see what's the most recent entries on glidersource.com. If they use a reader to read other feeds (e.g., news, etc) then it might work well for them. The feed is generated automatically whenever the user's reader calls the URL. So, once the programming for that was done, it's all hands off. I am NOT hand coding xml with every new listing, please!

Tim's site is the 800 pound gorilla in the glider ad category. Oh well. But I think you'll find that glidersource.com has the most comprehensive list of instruments, equipment, and other non-aircraft stuff (over 60 items at this time). I would assume that providing free ads for these items would conflict with "the retail operation", plus all the extra manual work.

(Bob's Genesis)[on glidersource.com] although, interestingly, it's also on Soaring Cafe's site
I don't see this as some kind of incongruency.
Bill Elliot, of Soaring Cafe, and I have conversed on several occasions and we support each other's efforts. We're both about helping folks buy and sell their stuff. Like I say on my home page: "Successful advertisers across many industries place their ads in many places, not just one." I think SC has its own niche audience (more contest oriented from my experience). I don't happen to care for the Wordpress plugin's format and paging that SC uses, so I wrote mine to work how I like. But neither of us are going to complain about an ad being on more than one website, much less checking to be sure they're not.

Ernst "Oh, what about get in your gliders that you purchased from wherever and have a good flight. "
I did go flying today! My first 1-26 flight. 10 ads posted automatically to glidersource.com while I was out there. Everything from tires to barographs - check it out at: http://glidersource.com/cgi-bin/post.cgi?action=recent