Just a suggestion...
I had this in my old site (poorly hand-coded php which is why I'm using wordpress & em now) where users could post an event themselves.
When the event expired (for example the art workshop was on Saturday and now it is Sunday) I had an automatic email go out to the person who had posted it reminding them that... your event has expired and would you like to add another event and btw here's a link to where you can post another event.
It was an excuse to send them an email prompt to post another event. Otherwise they would post their event on the website and possibly never come back.
Could EM maybe do this in the future?