Thanks, John and Frances, for your swift replies. You've pointed me to some very good resources, and I appreciate the help. The links you sent will be on my weekend browsing list.
Right now, as you may have noticed, I'm moderating the Scheduled Seminar here in SCoPE on the WebCT/Blackboard learning management system "merge". If we want to talk communities, those two have huge followings. As Frances can attest, there's also a strong development community around Moodle, which is a major challenger. I posed the question in the seminar about why people get so emotional over particular technologies, so if you have views on that, please step in.
Yes, John, I'll let you know how my presentation pulls together.