Microsoft admitted recently that Hotmail passwords have been revealed on a website, however, they have been removed since. Microsoft officials did not disclose how many accounts were involved, but some have estimated the number to exceed 10,000. Microsoft did say that this was not caused from breaching of its own servers.
Apparently the passwords were disclosed following a phishing attack. Phishing is generally done when a crook finds out sensitive information after sending a fake email that looks very authentic.
The website posting the passwords remained unknown and Microsoft stated all related Hotmail accounts were blocked and users were being helped to regain access to their email once again.