This is a design feature. The writeup search page is dynamic -- it takes CGI parameters and does a database call to generate whatever's shown.

If you hit the 'talk' button, you activate a different form, which passes no parameters to the writeup search form. Thus, it has nothing to display.

vroom put in the random user selector on a whim, based on who the popular users were way back then.

(Yes, this implies that the Everything Engine is rather stateless, but it also means that you can pass parameters to dynamic pages via URLs. Big surprise. :)