I have this notion more and more that the new face of email is actually a web page, albeit secured, and enabled with the directness of a wiki.
Two individuals rarely speak on a topic using a single email. It is usually a thread of communication. The idea of a "subject", "to", "from" all become implied for that thread of communication. Although these semantics lie in the heart of a POP server, as far as the UI is concerned it can just be a conversation on a webpage that is visible only to the specified parties.
Samething is true with groups or teams working on a project. Most of the times that communication needs to take place with the project as the background. Here again the communication can be on a web page with the email and the wiki integrated where the items are stored in a pop server where as displayed as a set of group items.
Seek and not react
Email is a perfect reactionary vehicle. We are used to the mode where if it is not in the email it will not be worked on. This is quite reactionary. An effective individual can rather monitor a set of activities that he/she is in control of and not necessarily driven by someone else.
Integrating pop and ui
The storage mechanism for this idea can still be pop and the existing email systems can be used perfectly well except that the vehicle for interaction with the pop is a web page or a collection of web pages that are secure and enabled for wiki. For instance when an email is sent it can just be part of the web page or when the web page is updated it can send an email.