I've written before about the data collected from Alfresco's Open Source Barometer survey. While originally a survey of 10,000 members of Alfresco's "content community" (i.e., those who register with Alfresco to download white papers, documentation, etc.), the survey now includes a swelling population of the community, with 35,000+ members.
The data becomes even more significant when you consider Alfresco's customer base: a high percentage include the world's leading financial services, media, publishing, government, and educational institutions.
So when I see Ubuntu at 23 percent of Alfresco's Linux user base (second only to Red Hat at 35 percent), with 51.3 percent of Alfresco's users choosing to deploy on Linux (with a scant 26.5 percent opting to deploy on Windows), I take notice.