Content Type Syndication is new feature that is part of the Managed Metadata service in SharePoint 2010. It solves a long-standing problem from SharePoint 2007, which is how do I create an enterprise library of content types and synchronize them amongst many different site collections. We often had to design and build solutions to work around this issue in SharePoint 2007, but now we have something that we can use out of the box. It's may not seem super intuitive in terms of setting this little gem up though, so use this document as a guide to get you moving in the right direction.

MOSS 2007

Say for example you have a Site Collection Web Application1 and you have created a series of content types to use. Now, you create Web Application2 and find the necessity to reuse the content types created in Web Application 1. There is no way you could share or reference those content types created in Web Application1 in Web Application2. The only way possible is to create or write an application which would install those content types. This situation is pretty common in large organizations. This can be even considered for exposing base content types you use across multiple web applications in the farm.

SharePoint 2010

SharePoint 2010 now introduces a new feature called Content Type Hubs. Content Type Hub is a central location where you can manage and publish your content types – so now web applications can subscribe to this hub and pull down the published content types from the hub. Even receive updates on the published content types!