The features include:
- Hotmail detects if legitimate user accounts are compromised and treats them differently than accounts that spammers setup themselves to send spam, working with the user to help them recover their account.
- New account proofs that identify which personal computers and Windows Phones are trusted to access your Hotmail accounts.
- More secure proofs. 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 is locked to prevent further abuse, and vacation auto-reply messages and linked accounts are suspended.
Windows Live and Hotmail will become more popular as Windows Phone 7 devices begin hitting the shelves in October/November. The more widely used, the greater potential for security threats.
The features are designed to address malicious accounts and to keep hijackers out of legitimate accounts. If you feel your Hotmail account has been compromised or are having trouble accessing it, you can visit Windows Live's Account Recovery site to re-establish your account.