In the issue tracker board it is possible to filter by custom fields but the same functionality is missing from the backlog board.

This inconsistency makes it very difficult to adopt custom fields.

Most changes for the product I'm involved in developing, need to be categorised by multiple features - it is very rare that one change will affect one feature.

I originally considered using the default components field, but this only allows you to set one component for each user story or bug.

I've also considered using tags but they become unmanageable, as there is no way to differentiate between different types of tags or control who can create new tags. I aware that you have 'special' tags but you only have one type of 'special' tag, so if you use them for more than one type of information it very difficult to know what tags for a particular kind of information is available - we've tried to implent a scheme where we put specific characters ('_', '+' etc.) at the start of a set of tags to group them together but this is not an good solution. Also, the fact that special tags can be created by admins is good, but you can't stop users from just creating a normal tag and ignoring the special tags. With tags there is no way to enforce a convention for categorising items in a specific manner, which is essential when managing a complex product.

A solution to the problem of not being able to categorise user stories and bugs by multiple features might be to enhance your 'special' tag functionality, but hopefully from my comments you can see that the obvious solution is to custom fields as they have all of the properties I've refereed to.

Finishing the implementation of your custom fields by making them available in all boards will greatly improve how Yodiz can be used to organise user stories and issues.