Facebook wants your number

Facebook is going to start asking users for their cell phone numbers–just in case they lose access to their account.  From Tech Crunch:

Facebook confirmed with me that the message will roll out to all desktop users over the next few days, and millions are seeing it right now. And while it might seem like a response to other recent security breaches on the web, Facebook tells me this security alert was planned before those happened. Well, break-ins to eHarmony, Last.fm, and LinkedIn should certainly get people clicking through.

Here’s how it’s a security bonus: Ii case Facebook is hacked or my account info is stolen, Facebook could send a new password to me on my phone right away.  
But it does seem kind of weird, right?  Can I really trust this company I hardly even know with my REAL phone number?  I mean, what if he’s a stalker or something?  Is this security progress?  Or data mining?