A List Apart is a web design weblog to which I subscribe (and read occasionally). Normally the topics deal with web design (i.e. how to design a good, standards-compliant web page), or web design project management (i.e. how to deal with clients).
So I'm more than a little curious to see this particular article about productivity improvements with a four-day working week. A few quotes, and you'll get the idea:
There will always be more to do. Working more wonâ€™t change that. In fact, working more is actually counter-productive. [...] The problem wasnâ€™t a time issue, it was a mental issue. I knew I had a whole week to finish my work, so I spread it out over five (or seven!) days. If I knew I only had four days to finish a whole week of work, it wouldâ€™ve motivated me to get things done more efficiently.
Working efficiently increases productivity.
Now if we can all do that.