What determines rankings in a site: search?

[Dennis-52961]

When I perform a "site:" search on my domains (without specifying a keyword) the top ranked results seem to be a mixture of sensible top-level index pages plus some very random articles.

Is there any significance to what Google ranks highly in a site: search? There is some really unrepresentative content returned on page 1, including articles that get virtually no traffic. Is this seriously what Google considers our best or most typical content?

[irvingw]

Matt Cutts explains how the site command works in this youtube video:

http://www.youtube.com/watch?v=Qigo05nAqKw&feature=player_embedded#!