Curious if Rules integration might be possible?

We have content which is updated for administrative reasons but nothing visible to most users. It would be efficient if notification could be sent only if a certain field has changed.

One other use case, for instance, right now the default option is to subscribe to the node and/or comments. Perhaps with Rules, custom events could be created. We have a lost and found site, so an option could be, when the status is changed to "returned home."

I understand the module is intended to be lightweight but thought I would inquire. Thank you.