http://msmvps.com/blogs/kathleen/archive/2009/03/20/assembly-organization-in-mef.aspxThe purpose of MEF is to hook up parts. Parts are indentified by string contracts. MEF (and tools like it) empower fully composable systems. I use that term to describe a system in which the system no longer knows what is going on. What you write empowersenCommunityServer 2008.5 SP2 (Build: 40407.4157)