[cyberferret]

...or they will be the very thing that frees up your users to use them in creative ways without feeling hemmed in to a particular mindset.

We have the concept of 'tags' in our app, which are used by our users to delineate anything from company departments, social groups, locations, age bands etc. - basically anything they see fit. It saves us creating a mess of drop downs to try and cater for all edge cases, and they feel the freedom to think of them however they like.