TinyLetter is a message silo and service to organize email newsletters, with an optional blog-like web archive, that was acquired by MailChimp in 2011. Sometimes used as a simple blog with restricted viewership.
How export data
Subscriber lists can be exported as CSV, past posts not(? at least not documented).
How to delete your account
Has anyone deleted their TinyLetter account? What's the process? How long do they hold your data anyway? Etc.
How to POSSE
Does anyone POSSE to TinyLetter? For what reason?