A number of new features designed to improve security to get rid off Hotmail's malicious accounts were announced. These new features can make it easier both to keep "hijackers" out of your legitimate accounts to begin with, and also to make it easier to get your legitimate accounts back:
- Hotmail detects if legitimate user accounts are compromised and treats them differently than accounts that spammers setup themselves to send spam, working with user to help them recover their account.
- Cell phone number and option to register your PC as "Trusted PC"
- Previously (and still on other services), users could add/remove proofs with just their password. Now, the ability to validate an existing proof is required to change them.
- Closing back-doors the hijacker may try to leave open. When a compromised account is detected, it's blocked to prevent further abuse, and vacation auto-reply messages and linked accounts are suspended
More Info: Account Recovery