In this post, I will describe few improved features in SharePoint 2013.
SharePoint 2013 has cross-site publishing. In the previous versions of SharePoint, it was not possible to easily share content across sites. Using cross-site publishing, users can separate authoring and publishing into different site collections: authored content goes into an indexable "catalog", and you can then use FAST to index and deliver dynamic content on a loosely coupled front end.
This feature is required for services like personalization, localization, metadata-driven topic pages, etc. An example of its use is a product catalog in an e-commerce environment. It can be used more generally for all dynamic content. Note that cross-site publishing is not available in SharePoint Online.