Needpedia has no offsite notification system

We need a way for people to know if someone's interacted with content they've posted, without having to log into Needpedia all the time to check.

In other words, if you've posted about a problem or shared an idea, you're probably going to want to know if there's been a new development. 

A notification system's been attempted in the past but it doesn't seem to work. Notification systems increase user engagement so it's extremely important to get this handled before trying to go public.