Thanks for writing! Your guild actually sounds a lot like mine. And although our Web site isn't exactly a high-budget affair, most of the people in the guild visit it from time to time and a large portion of those are active posters. Even so, I still have moments like the one a few weeks ago. I had posted some info on how to obtain the Gruul's Lair-specific flasks, bumped it to keep it visible, and even cross-linked it in a few other posts to make sure people saw it. Then when we set out to do the Bash'ir Landing Skyguard event on the night of the raid, people were still asking me, "What are you guys up to in Blade's Edge?" and "How do I get Apexis Shards?" It can be quite maddening.
But for the most part, people are quite active on our site. I attribute the success of the site to two things: desk jobs and boredom. If your guild is full of white-collar types, I can virtually guarantee you some daytime traffic.
Beyond that, the first step is to build awareness. Put the URL in your guild's Message of the Day and on the info page in the guild interface. Use the site to do some of your important ongoing business like announcing raid schedules. That way, your members will get in the habit of visiting the site if they want to stay on top of what the guild is doing.
Once you've done that, you need to give people reasons to visit it often. And much like this crazy Wow Insider site, you have to offer new content on a frequent basis to keep people coming back day after day.
The easiest way to generate new content is to keep your forums active and interesting. Your forums are the key to building a thriving community on the site. I check our site probably 4 or 5 times per day during the week, and rarely do I log in to see that there aren't any new posts. I look at other guild's sites and see threads on the first page that haven't been posted in for weeks. Even some of the big, famous guilds have stagnant forums, and I've never understood why.
What do we post there? Anything and everything including raid rosters and run schedules of all sizes; jokes and funny screen shots; original game guides about classes, quests, professions, etc.; the guild banks' contents; personal updates about what we're up to IRL; polls to get feedback; random smack talk; our rules and philosophies; salutes to our victories and examinations of our defeats to improve our performance; applications for new members; political and scientific discussions; and of course pics of members' drunken exploits at guild parties.
It takes a while to get to this point, obviously. Since you don't have an army of bloggers at your disposal, you have to rely on your members. As the guild leader, make a new thread every day and ask your officers to post in it or start their own threads whenever they can. The topic doesn't matter, as long as it's useful or entertaining in some way. Don't make your posts only about Warcraft or only about serious topics -- get creative and let loose! Posts beget posts, and if you keep at it, other people in the guild will catch on and start posting as well.
Another easy way to encourage posting is to offer ranks for the number of posts people make. The officer who made our site has a goofy sense of humor, so his ranks are pretty off-the-wall and people can't wait to see what the next highest rank will be. Our most active posters hit the 2500 mark a few months ago (and this after our entire site's database accidentally got deleted about a year after its launch), so we have quite a few ranks at the moment.
I'm sure other guild leaders can chime in below with what makes their sites unique and interesting. My guild's site is pretty standard, but our community has made it a special place that people rely on for good information, guild management, and -- most importantly -- endless entertainment. Your community can too!
Send Scott your guild-related questions, conundrums, ideas, and suggestions at firstname.lastname@example.org. You may find your question the subject of next week's Officers' Quarters!