@skisma i think that was just a mockup from this website in the link below
and the author of this topic just stumbled upon it.
and since this is from 2009 it is most likely the bbpress standalone version 1.0x and such
but you could accomplish close to the same result using wp-usersonline plugin and also the inbuilt stats shortcode and just a little bit of CSS.
create a new topic about this though.