Interesting idea.
On that basis, statistically, based on 22800 images posted recieving a total of 73600 comments or an average of 3.229 comments each your best chances of getting a POTW winner are:
Category
_____________Ave Comments
People
___________________3.683
Manipulated Images
________3.676
Still Life
__________________3.580
and least likely to be selected would be
Transport
________________2.465
Plant Life
.________________2.411
Sports & Action
___________2.268
Of course there are lies, damn lies & then there's statistics
