A few weeks back my credit card was unexpectedly cancelled and reissued to me with a different number. Now a friend tells me her's has been cancelled too. The common element: recent purchase from NewEgg.

Anyone else?

Not yet. I sure hope newegg hasn't been compromised.
If you find any concrete news about this on the web please post it here, I'd really appreciate it.

In my opinion it is unwise to let anyone hold your credit card information on file. It is just too juicy of a target to get thousands of valid numbers in one hack success. Can you say 'Identity theft?'

Pretty hard to avoid, if you do much buying online. What I do is use a visa debit card (I know, I know) reserved only for internet purchasing... I keep only the needed amount of money in the account, so if it's overdrawn I can cancel the card immediately and get the bank to do an investigation. My bank has excellent online account access, so that helps greatly.

One time, my debit card number & info did escape on the Net... somebody racked up some charges at pr0n sites and such. It was a big hassle, but I called all the sites in question and got refunded, my bank investigated and I switched to a new account. Didn't lose any money over it, just some time and hassle.

Many sites have a check box that says 'do not keep card information on file.' Be sure to check it.