Time and again, when security breaches reveal large numbers of user passwords, analysis shows there are particular passwords commonly used by a significant percentage of the userbase. Now, an anonymous reader tips news that Hotmail is trying to do something about it. "We will now prevent our customers from using one of several common passwords. Having a common password makes your account vulnerable to brute force 'dictionary' attacks, in which a malicious person tries to hijack your account just by guessing passwords (using a short list of very common passwords). ... Common passwords are not just 'password' or '123456' (although those are frighteningly common), but also include words or phrases that just happen to be shared by millions of people, like 'ilovecats' or 'gogiants.'" This comes alongside a new feature that lets users send a report indicating a friend has had their account hacked.