Post date: Nov 04, 2014 1:50:41 AM
I struggled to determine why I was unable to add a WFS to ArcMap using the standard server connection for a few minutes before I gave up and started googling the issue. Apparently, WFSs cannot be added without the Data Interoperability Extension installed. That provides a category in the catalog window called "Interoperability Connections". It is here where one must add the WFS connection, and then the WFS data can be added to the map document.
The full details of this process can be found in the help at http://resources.arcgis.com/en/help/main/10.1/index.html#//00370000000p000000.
Also, be sure to have the WFS URL so it can be entered into the connection dialog. To get this URL, check the server manager page for the service, or look at the map service properties for the WFS through the standard server connection (all web services must have a corresponding map service). The WFS tab in the capabilities will have a URL.