Here are some that I found interesting and/or beneficial:

Visa actually stands Visa International Service Association.

You can lower your interest rate with a phone call. Credit card companies are like cell phone and cable companies, they’re afraid you’ll leave and join with one of their competitors. Use this to your advantage by comparing offers from other credit cards and bringing this information to your credit company.

Hotels and rental car agencies usually send an authorization request for the estimated cost of your stay or rental and they keep this “block” on your card for 10 to 15 days (independent of how long you actually stay there) even if you pay with something else.

Ever notice all your credit cards are of uniform shape and size? Their dimensions are governed by the ISO 7810 standard, an international standard for identification cards. Banking cards, as well as driver’s licenses and retail cards, follow ID-1 (passports follow ID-3).

The first six digits will correspond to the issuer, including the major industry identifier. 34xxxx/37xxxx are for American Express, 4xxxxx is for Visa, 51-55xxxx is for MasterCard, and 6011xx is for Discover.

Credit card companies earned $90.1B in interest in 2006, up from $89.4B the year before (according to R.K. Hammer).

Read the rest here.