Mailing List App

I'm looking at options to improve the user experience for a mailing list (announce only) service. Right now, my organization is using Mailman. It seems to me that the Creator platform could provide a very nice mailing list service with features only available on high-end mail apps. For example:

a newsletter could be personalized with "registered" user's names
personalized "un-subscribe" links could be added to the bottom of each email (url encoding to stateless forms)
user's could have a dashboard page listing their subscription prefs
Forms to subscribe and unsubscribe
Commands by email are possible

However, this presents a few questions...

Is this type of app OK with ZOHO?
What is the rate of delivery? 10 per hr, 100 per hr, etc?
Are bounced emails sent back to the app's admin?
What happens if more than 500 emails are sent in one day?

Thanks