When an idea is promoted to a feature/master feature, it would be helpful to display within the Ideas Portal any release details associated with the new feature, for portal user reference. This would be more effective than using watcher email updates, as those can easily get lost/forgotten, whereas always making this visible within the Ideas Portal means it's easy to look up on demand.
Thank you for your idea. There is a work around that would allow to do this currently. You can add a Release custom field to your ideas portal and set it manually when you know which release the related feature will be delivered in.
Given historical feedback and current priorities, along with the ability to manage this using custom fields, we are unlikely to implement an automated way of handling this at this time. We hope you can understand.