automatically capturing email addresses in contacts?

[kbf]

My organization will be shutting down the service that allows us to access email using the zimbra web interface and desktop client. Currently, zimbra "remembers" many email addresses that are not stored in my address book. Is there some way to have it pull all these email addresses into my address book so that I can export them? (or some other way to export them)? Thanks in advance for any assistance.