My credit card companies are so good at identifying fraud they've caught 17 of my last 0 fraudulent transactions.

(OK, I sympathize: buying a thousand bucks of stuff in four transactions from central Japan at 2 in the morning is not exactly typical behavior for a Bank of America customer.)

Yes, but for the most part those will be swipe transactions, not online transactions. And they keep an eye out starting at $100 or so because that's when it starts to add up if you fail to spot a fraudulent charge. The majority of online transactions is pretty small though, and falls right in the gap between 'don't care' and 'card issuer spots fraud'.

Interesting. Mine (Barclay's) is overly aggressive: it calls me every two weeks, and blocks my cards about 4 times a year.

I have pre-paid phone, buy small items from Google checkout, and travel frequently. Barclay's knows this, but still keeps calling to confirm my (quite regular, very normal) transactions and blocking my cards.