I just found this and think it is quite informative if anyone is interested in reading in regards to the Visa/MC Anti Trust case which goes to trial next year.
Legal stuff:
http://www.usdoj.gov/atr/cases/indx57.htm
"Count II focused on Visa's Bylaw 2.10(e) and MasterCard's Competitive Programs Policy (CPP) (together, the "exclusionary rules," Op. 329 (SPA165)). These rules permit member banks to issue credit and charge cards on both the Visa and MasterCard networks,(2) but prohibit them from issuing cards on the only two other major general purpose credit card networks, which are not controlled by banks: American Express (Amex) and Discover. Op. 329 (SPA165). Plaintiff contended that the exclusionary rules restrained competition among credit card networks and credit card issuers, and thereby harmed consumers."