The WatIn doc page (http://watin.org/doc/index.html) is out. I found this link at http://watin.org/documentation as a link to "MSDN style online documentation".
Yeah, I think it's been this way for a long time now.
These kind of things basically tell me to keep away from a project a go find an alternative that is maintained.
Actually I had more troubles with WatiN and with my next project I think I'll use either Watir or Selenium.