I subscribe to a bunch of open source WCM mailing lists. Occasionally, someone announces a new site that he/she built on top of the platform. When I read this, I usually tag the site on del.icio.us with a tag like <cmsname>gallery. For example: "bricolagegallery". Many open source WCM project sites already have nice reference site galleries with descriptions about the technology used. I find del.icio.us tagging useful for sites that are not on the public galleries. Here are some tags that you might find useful:
If you have a reference site that you would like to put up on a CMs project gallery, you should send an email to their mailing list. If there is no gallery or you just want to put something up right away, tag it in del.icio.us.