The category tag shouldn't have text other than the label

My reference article: http://edward.oconnor.cx/2007/02/representing-tags-in-atom

![screen shot 2014-11-04 at 9 02 17 am](https://cloud.githubusercontent.com/assets/430385/4900744/36205c32-642b-11e4-9a79-b4a8be30d12f.png)


See: https://github.com/GigaOM/gigaom/issues/5883