Its the different teams that are playing.
The Pittsburgh Curling Club (or PCC) is a curling club located in Pittsburgh, Pennsylvania. It is one of only four curling clubs in Pennsylvania, the other three being the Philadelphia Curling Club, the Bucks County Curling Club, and the (formally the Scranton Curling Club). The PCC is an arena curling club that was founded in 2002 with 12 members, and as of 2009 it has grown to include over 120 members.
The World Curling Federation (WCF) is the world governing body for curling accreditation, with offices in Perth, Scotland. It was formed out of the International Curling Federation (ICF), when the push for Olympic Winter Sport status was made. The name was changed in 1991.
The ICF was initially formed in 1965 as a committee of the Royal Caledonian Curling Club in Perth after the success of the Scotch Cup series of world championships held between Canada and Scotland. At the outset, it comprised the associations of Scotland, Canada, Sweden, Norway, Switzerland, and the United States. In the wake of its formation, it sanctioned the World Curling Championships. The WCF currently sanctions fifteen international curling events (see below). The WCF is managed by an executive board of seven, each from a different country and elected by WCF member associations, and a permanent staff of ten employees. There are currently 50 member associations.