BitDreams & Injust: So by your definition, I have found a security bug _in hotmail_, by going to google, searching for a hacked database dump of some random other site (i.e. not hotmail), find a random user with a @hotmail email and try to login to his mail by reusing his password from the other hacked site. If this work (which it does with enough tries), then it would be hotmail.com's fault? This is what your saying right now 
I suggest you read this: https://bitcointalk.org/index.php?topic=159025.msg1695310#msg1695310 basically the founder's "flaw" (which has been known for ages) is about finding people who leaks their private keys (just like leaking your mail+pass). Not protecting against this, is not - and will never - be a security flaw. It is, as I've said before, best practice to do whatever you can to stop user errors, but it the end it's the users fault. To quote Albert Einstein: "Only two things are infinite, the universe and human stupidity, and I'm not sure about the former."
I suggest you read this: https://bitcointalk.org/index.php?topic=159025.msg1695310#msg1695310 basically the founder's "flaw" (which has been known for ages) is about finding people who leaks their private keys (just like leaking your mail+pass). Not protecting against this, is not - and will never - be a security flaw. It is, as I've said before, best practice to do whatever you can to stop user errors, but it the end it's the users fault. To quote Albert Einstein: "Only two things are infinite, the universe and human stupidity, and I'm not sure about the former."