I would imagine there are millions of Verizon webmail users but judging by this thread there is not an overwhelming demand. http://forums.verizon.com/t5/Share-Your-Ideas-with-Verizon/IMAP-e-mail/idi-p/238138/page/3
Personally I use Zoho as my primary email system & there are others that offer IMAP support as well http://email.about.com/od/freeemailreviews/tp/free_email.htm
