‘Syndication’ is a common term heard on broadcast television. The objective behind syndication was to rerun a show that had mass appeal and still had the ability to generate revenues for the production house. These syndicated shows were then licensed to other networks in return for a fee.
Content Syndication likewise works on a similar principal. The shelf life of popular content that has mass appeal is extended by permitting other content publishers to publish this content on their own sites. Instead of asking for a fee, the author requests a link back to the source of the original content. This brings in greater quality of organic traffic to the original content and improves their visibility.
The exact nature of the above arrangement would vary from link back to a fixed fee to a performance oriented model.