Andre has it right, and if you dig into the very oldest email archives, you will find that the inventor of the "talk page" was Tim Shell, later a board member of the Foundation.
Andre Engels wrote:
2007/4/2, Nicholas Moreau nicholasmoreau@gmail.com:
Okay, maybe it wasn't you, but I remember hearing (don't remember the source) that before Wikipedia was launched, everybody discussed everything on the mainpage, mainly because there was no talk page feature. I guess I'm just spreading stories.
I know that in the old days of Wikipedia, discussion pages were normal pages titled [[Title/Talk]]. On the page itself, a link could be created with the text [[/Talk]]. The current method of having a specific namespace for that was I think created together with the current software, in which case Magnus Manske would be the person to praise for it.