browsable folders and the query string
was pretty confused about the "C=M;O=D" string found appended to most of the browsable folder URLs indexed by Google. but finally figured out a way to make sense out of it..

The query string is used basically to sort the list of files that appear.
C is for the column name on which the list is to be sorted. O defines the sort order..
O can be either A or D for ascending and descending sort respectively..
Not sure about all the values that C can take.. but these ones work:

N - Name i.e. file name
M - Last Modified date
S - Size
D - Description (havent tested this)

not sure if this's web server specific.. but many such URLs I got were from Apache..