Re eMail overload at big organisations

A couple of friends were telling me last night about the eMail overload they have at their company. 100-200 emails per day (not including spam) all of which have to be scanned to see if they are:
- genuine requests for action
- replies
- just thought you would like to know
- does anyone know....
- arse covering
- arse licking
etc.

We considered a number of solutions from charging people to send emails to banning email altogether, but here was the best idea of the evening.

• Email is for actions only, ie. the first two in the list above
• You can only send email to one person
• You, generally, use the old fashioned chain of responsibility when sending - ie. you send a level up or down, NOT to the whole chain. It is the responsibility of the person you send to whether to forward your email. Structures are fairly flat these days, so not as onerous as it used to be.
  
• All cc's get put on a public (to the organisation) twitter stream instead of being delivered. Can also post direct to twitter stream.
  
• It is NOT expected that everyone will see everything on the twitter stream, but it allows for some element of serandipidy - MD just happens to see cleaners observation re competitions plans leaked to girlfriends, mothers, step-brothers, aunt....

Interested to hear any ideas or experiences of what has worked as huge potential savings here for many organisations! Is it possible to process emails before delivery and remove CC'd people then post text on internal twitter? Would need to notify people their email had not been delivered to everyone, by email, thus increasing the number of emails again!