Yahoo and Verizon
Mickey at Spamtacular has information about Verizon’s email system that will have relevance for anyone working in delivery.
Verizon has partnered with several megaportal sites depending on which Verizon service a subscriber is using. FiOS customers can pick between AOL and Yahoo while DSL customers get AOL, Yahoo, MSN Premium, or Windows Live to select among. The portal site that you select may also impact email routing.