I'm reading a lot of opinions about Facebook's rumored "Gmail killer". I'm curious about the specific characteristics of any web mail that HNers would consider valuable? I am NOT referring to the solution of setting up your own domain mail server and linking it to browser interface or mobile client. I can think of two: (1) Easy download/backup: API for fast batch import/export, zip files via browser, etc. (something beyond IMAP). I would be willing to pay extra for this service; (2) Providing reasonable assurance that data associated with my account or with individual emails do not persist after the account or the emails are deleted. I admit the second characteristic is theoretically impossible without complete control and audit of the hardware. I hope someone can propose a novel transparent process (such as data being stored in escrow or audited by certified third party or something). What specific characteristics would you look for?
Shared mail folders with the ability to set up proper read/write ACL's.<p>Delegation<p>Undelete messages<p>Delayed sending (Send at yyyy-mm-dd hh:mm:ss)<p>Import mail via IMAP/POP3<p>Export mail via IMAP/POP3<p>An alternative LDAP interface for reading/writing contacts<p>Thread muting so you can ignore entire threads including messages that arrive after you've muted it.<p>The ability to view the SMTP logs for a message in Sent Items to see if/when the remote server accepted the message.<p>RSS folders.<p>Message filtering in the Sieve format<p>PGP support. Public keys can be stored server side and used for signature verification and to encrypt outgoing mail. To perform operations that require access to the private key such as decrypting incoming mail, and signing outgoing mail you'd have to install a browser plugin which interacts with the website. Not ideal, but the only "safe" method.<p>100% SSL encrypted browser sessions.