Danny – Thank you for pointing me in the right direction. So, your plugin just handles registrations into the MailChimp list. Then, I would setup a campaign within MailChimp (not your MailChimp for WP plugin), using RSS to drive a weekly summary. OKAY… it’s really simple NOT, but I get it!
I think what confused me was that I personally was getting an email notification every time I published a new post. It maybe Jetpack is doing that via www.ads-software.com. So many pieces to this WP infrastructure!