While I appreciate the resurgence of personal email newsletters as an alternative to the toxic walled-gardens of Social Media™, I much prefer consuming that type of content in my feed reader.
For discussion groups, where I’m going to respond to messages and follow threads, email is great. My relationship with the newsletters I subscribe to is that of a consumer, and for that interaction I want good old HTTP and feed syndication. Kill the Newsletter is a free service that generates Atom feeds from the email sent to an address. I use it to keep newsletters in my feed reader where they belong.