Here’s a bad piece of news. Our cell phone numbers becoming a lot like Social Security numbers: they are the gateway to our identities, providing an entrance to personal data – your email address, physical address, even physical whereabouts—and all the personal information that is kept about you by nearly all corporations, financial institutions, and social media networks. Yet when we are asked for our cell numbers for whatever reason, we often give them out without even a second thought. What can you do? Take a look at these tips and use common sense. If you are asked for your phone number, it never hurts to ask why.