In SharePoint 2010, we saw the introduction of Service Applications, like the User Profile Service, and the breakaway from Shared Service Providers (SSPs).  This provided a much more scalable architecture for administrators that was easier to maintain.  If you ever worked with SSPs in the past, you knew that they were prone to break and were very difficult to work with at time.  Another improvement made in 2010 were the social features, such as ratings, likes, tags, and notes.

In SharePoint 2013, we are going to see some new features, but more importantly, we will see improvements and optimizations.  The User Profile Synchronization Service has been optimized so that it takes less 'jobs' to sync with data sources, such as Active Directory.  In SharePoint 2010, a full sync with AD could take 6-8 steps.  But in 2013 we have a new connection type called Active Directory Import, which does a direct import from AD with nothing being written back to AD.  This makes imports much faster and it only takes about 4 steps.

Another performance improvement change was moving the 'processing' of synchronization from SharePoint to the FIM process.  SharePoint no longer handles the communications directly with the user profile source.

One of the new features is Micro-blogging, which I'm excited about, but I will cover that in another blog post.

However, there is a downside to moving to this new Active Directory Import connection.  There is no direct migration process from the traditional sync connection type.  You must setup a new connection, filter, and property mappings.