MB Term Meta is an extension for Meta Box plugin which allows you to add custom fields to taxonomy terms like categories or tags. The plugin supports all field types from Meta Box and uses the same UI as WordPress admin area.
Adding metadata (custom fields) for taxonomy terms is important since it allows us to add more data to term objects. These data allow us to add a more visual description to the term objects beyond the default description which can help us designing in the front end.
There are a lot of info that can be useful for terms. This is just an extremely small sampling of ideas:
MB Term Meta simplifies the process of adding custom fields to terms by using the same syntax in Meta Box for posts. No more learning curve when using this extension.
Besides, it supports all the features from Meta Box such as all field types, cloning and validation.