Excel Services

Excel Services
Excel services provides the ability for information workers to show the excel file in a web page. Those accessing the web page do not need to have Excel installed.  Some features include:

• Global settings for managing workbooks (e.g. security, load balancing, session management, memory thresholds, caches and external data connections).
  
• Management of SharePoint repositories to trust for Excel Services
  
• An extensive list of trusted data providers for connecting to your data, plus the ability to add your own trusted data provider.
  
• Trusted data connection libraries, which allow you to define which data connection libraries in your farm are trusted by Excel Services.
  
• The ability to add your own user-defined function assemblies.
  

A great overview of this is given here:

http://technet.microsoft.com/en-us/library/ee424405.aspx

For SharePoint 2013, there are additional features related to developer functionality in creating Excel Interactive Views related to Excel Services. The key additional functionality lies in the business intelligence integration that now exists between Excel 2013 and SharePoint 2013 – particularly related to the creation of scorecards, reports and dashboards; all of which can be brought into Excel and used to create these which can then be easily displayed in SharePoint 2013 sites. See the following link for further information:

http://technet.microsoft.com/en-us/library/jj219751(v=office.15).aspx

Another excellent feature is of course Pivot-Table, there is a wealth of information on this link that describes what it is, analysis services and how to use this feature:

http://blogs.msdn.com/b/analysisservices/archive/2012/08/02/verifying-the-excel-services-configuration-for-powerpivot-in-sharepoint-2013.aspx