Bluematter.

Or is this a tax on emailing?

Attent™ [...] tackles the problem of information overload in corporate email using psychological and economic principles from successful games. Attent creates a synthetic economy with a currency (Serios) that enables users to attach value to an outgoing email to signal importance. It gives recipients the ability to prioritize messages and a reserve of currency that they can use to signal importance of their messages to others.

More here. I have reservations:

1) Who is responsible for controlling the currency supply (and will internal corporate communications enter a boom and bust cycle?)

2) Can a goods market work without a credit market to enable capital to find its way to its most productive use?

3) Will the reduced informational cost faced by the readers compensate for the increased informational cost faced by the senders?

4) Is the system incentive compatible? Do senders' valuations correspond to those of the readers, even on average?

5) Does this formal system offer much at all? Don't we already have ways to show that a particular piece of information is important? (the word URGENT in the subject title, coupled with a couple of follow-up calls, together with a reputation for not sending useless email does it for me)

On related news, in today’s America there are more World of Warcraft players than farmers.