How Big Is Sheffield as a Football Base?

This is a genunine question and not intended to stir (although I do know we have a resident SWFC fan)

I was looking through my most viewed photos and 3 out of the top 4 all time were Sheffield related, wasn't too sure whether they both are popular teams on the internet, or it was both teams sending links to wind the opposition up

#1: http://www.flickr.com/photos/joncandy/4 ... /lightbox/

18/12/09 Deep in the depths of the CCS the boiler room is a hive of activity
• 2002 views / 1 person counts this as a favorite / 1 comment

#2: http://www.flickr.com/photos/joncandy/4 ... /lightbox/

24/03/10 Cardiff v Sheffield United, Championship, Cardiff City Stadium, Cardiff, Wales
• 1503 views / Nobody counts Sheffield United Away Fans as a favorite / 1 comment

#3: http://www.flickr.com/photos/joncandy/4 ... /lightbox/

08/08/10 Cardiff V Sheffield United, Championship, Cardiff City Stadium, Cardiff, Wales
• 1356 views / Nobody counts Directors Box V Sheffield United as a favorite / 0 comments

#4: http://www.flickr.com/photos/joncandy/4 ... /lightbox/

24/04/10 Cardiff V Sheffield Wednesday, Championship, Cardiff City Stadium, Cardiff, Wales
• 1333 views / 1 person counts this as a favorite / 0 comments