It is possible to get direct IMAP access. Yahoo! operates IMAP and secure IMAP servers (imap.mail.yahoo.com in particular), which are globally accessible. However they require a specific, non-standard IMAP command to be sent before login is done, namely: “
ID ("GUID" "1")”. This non standard command is not required if accessed from mobile networks, typically those used by smart phones on mobile carriers such as AT&T, T-Mobile, etc… For regular internet users, it is feasible to modify an open-source e-mail client to send the ID command, and there are modified versions of Mutt and Mozilla Thunderbird available to download.Alternatively, one can connect an unmodified e-mail client through an IMAP proxy that adds the ID command. A commercial software package that accomplishes this is called ‘Yahoo IMAP Connector’, available here. Mutt-dev (1.5) works without any modifications.
It is also possible to send mail through mail clients as Yahoo! also operates an SMTP server (smtp.mail.yahoo.com). It is necessary to enable SSL through port 465. For IMAP and SMTPS access the username is the user’s Yahoo! Mail address and the password is the same as for webmail access.
Strange decision on behalf of Yahoo! Mail to not support IMAP for all email clients. One that is a deal breaker, I must add…