Here's a feature request for Google's Gmail system. In the same way that one can designate sharing of calendars, allow sharing of Gmail accounts. Several organizations I work with have Gmail accounts for various purposes. Today there are two options to share these accounts. The organizational account can be setup to forward to a number of users, but this leaves my inbox a jumble of personal and organizational emails and leads to the second option. That is to log out of Gmail and log back in as the organizational user. Something I do several times a day but it's tedious on several levels, including that the other Gmail services I use are tied to my personal account.
It would be great to have the same sort of sharing options as the Google Calendar service (pictured above). You could then designate others who could read your email, or those who could read and respond on your behalf. This feature would catapult Gmail further ahead in the web-based desktop arena.