3/ Other HH mail is the residual household First-Class Mail with the following major  financial statements, announcements/ meetings, notices of order, request for and confirmation of donations, tax forms, education acceptances, and insurance policies.
Major financial statements and tax forms are usually shipped with First Class Mail.
Insurance policies receive no special considerations when they are mailed.
The U.S. and foreign mailers would likely prepare AO mail.
A man is singing
Slate accepts people for participating as voters in their Hackathlon.
a man sleeps outside a window
Travel connections between separate island chains are numerous and easy to find.
Heroes of the Computer Revolution by Steven Levy is source that offers more information.