Also, FB should allow users to: create multiple inboxes; forward messages within FB to friends; import address books from other services and clients; convert addresses of contacts who are not on facebook or who are not on the user's friends list, to 'pseudo-friends' (aliases or nicknames) and allow users to create pages for the pseudo-friends that are accessible only to that user; allow users the option to create an easily-filterable facebook.com address so that external (non-FB) friends can, if the user wishes, send email directly to the FB Inbox.

FB should explore permitting users to configure their email system so that they can use more than one email address, including addresses linked to other FB accounts, from one 'master' inbox page.

These are just off the top of my head ideas. I'm sure I could come up with a dozen more, but the point here is that FB has ignored the potential demand for a fully-configurable email function that permits users to easily communicate with external-to-FB contacts. FB has a major advantage over other free-mail services in that it can offer much more fine-grained spam controls, both incoming and outgoing, and security in general. At least it seems intuitive to me that this is the case, since so much email could potentially be internal and thus more easily monitored for malware, botnets, etc. FB could offer users a much safer email experience than elsewhere.

Facebook enables developers to add stream attachments to messages, as seen within wall posts, but I'm not familiar with actually embedding applications within the message. I was unable to find any information on the Facebook Developer wiki, stating this was possible.