I was reading interspire's features, and one stuck out:
"Interspire Email Marketer is 100% unencrypted and modifiable. You can
modify the code to suit your needs and even build new add-ons using the
modules framework if you know PHP."
That would be cool to have a Module Add-On feature for arpReach, so users (or other companies) could code their own custom addon module and integrate with other services. Or we could custom program our own addons and share them with others in some kind of arpReach open marketplace.