Why Facebook asks me for a phone number, when I try to sign up for a Facebook account?

When you sign up for a Facebook account, if will ask you for a phone for 2 reasons:

• It will send you a text message to verify your identity.
• If will check existing accounts to ensure that only account can be created for a single phone number.

Here is the answer from Facebook on why they need to verify identity by checking your phone number: "We want to make sure that this is really you and that you’re connecting to Facebook with just one account."

here is the answer from Facebook on why you can't use your phone number to verify multiple accounts: "We use the phone number connected to your account to help identify you in the same way you might use an email address or username (ex: you can use the phone number on your account to log in). Because your phone number is used to uniquely identify your account, you won't be able to use the same phone number to verify multiple accounts."

⇒ Integrating Website with Facebook

⇐ Too Young to Use Facebook

⇑ General Questions on Facebook

⇑⇑ Facebook - Frequently Asked Questions