It is truly a community effort
We released Chef on January 15th, 2009. As of March 17, 2012, more than 630 people and 120 different companies have signed up to contribute to Chef. Companies like Engine Yard and Right Scale have integrated it into their business offerings directly.
Many different cookbooks, automating everything from Apache web servers to Xen virtual machines have been published, and put to work in completely different environments.
When you use Chef, you join a community of professionals who have been there before, understand the problems we all face, and are working together to make things better for everyone. The results are far greater than any of us could have possibly achieved alone.