From the Sacramento Java Users Group blog:
At the last SACJUG meeting we debated over what wiki/content management system to use and eventually settled on Confluence. The feeling was as a java users group we needed to use a Java based tool. I volunteered to see if they’d grant a license since my company is already a Confluence customer. About a week later I got a nice email from Atlassian granting SACJUG the right to use Confluence for site.