I've lost my iPhone so currently only using web interface but it seems like the only options for notifications are when -

Someone adds me as a contact
Someone joins Remember the Milk after I invite them
Someone gives me a task
Someone shares a list with me

Apologies if this is a duplicate suggestion but I searched previous suggestions on "notifications" and couldn't find any that seemed to cover this.

https://www.rememberthemilk.com/forums/ideas/?q=notifications&Search=Search

I specifically would like to have the option to be Notified when a Note has been added and also when Tasks are closed.

The software engineer in me would love to to see every state change on every entity (Task, SubTask, List, User etc) available as a Notification that can be easily and flexibly managed but I understand the user experience challenges that would present across multiple platforms!