some questions about Plugins Page

Hi
how are the plugins rated and sorted in the "Browse Plugins" ==> "most
popular" link?
It doesn't seem that they are sorted neither by the average rating nor
by the number of votes.
is there any other criteria? (like downloads)
also the "browse by date" does not seem to work. is it supposed to be
the same as "latest releases" but listing only the latest version of a
plugin?