It’s become somewhat fashionable in the tech community to hate on phone numbers. In fact their impending death has been predicted for years. In 2010, a guest post in TechCrunch proclaimed that phone numbers are dead, they just don’t know it yet. The Verge published a survey of all the services that were about to kill phone numbers in 2011. But like twinkies after a nuclear apocalypse they live on, forming the backbone of the largest social network in existence.

Setting aside landlines, there are 3.2 billion mobile phone numbers in use today. That’s three times more users than Facebook has. Clearly they’ve got some kicking and screaming left to do before they kick the bucket. So let’s explore some of the reasons phone numbers became so ubiquitous, and why they’ll keep defying the technorati for many years to come.

Phone numbers are simple.

Phone numbers are just numbers. There are no letters or other characters to translate. If I give a business card to someone I meet in China, he or she can immediately identify the phone number and will know exactly what to do with it. And phone numbers are also much easier to tell someone out loud than, for example, an email address. No need for “that’s ‘D’ as in ‘dog’” and other pesky explanations.

Phone numbers are flexible.

There are countless devices that work with a phone number, and we are each free to choose those that we like best. But importantly, my choice doesn’t impact yours. If you want to use an iPhone, I can still call you on my old Motorola Razr (if I could just find the charger).

Phone numbers are shareable.

Put a phone number on a website, billboard or t-shirt and anyone can call you. Need to text a friend-of-a-friend? Just ask for their phone number. There’s no invite process required. And if you don’t want someone to call or text you, don’t give them your phone number. No need to configure any permissions settings in a complicated web-interface somewhere.

A phone number now identifies a person, not a location.

In the olden days, before mobile phones and number porting, a phone number identified a location. Most people had a home phone and a work phone, with separate numbers. The home phone would actually be shared by the whole family, except for the lucky kids whose parents got them their own line.

Now that mobile phones are ubiquitous and we can keep our numbers when we move and switch carriers, the phone number no longer identifies a location. It identifies an individual. This mapping strengthens the bond between a number and its owner. And the increasing strength of that bond is what keeps the phone number network strong.

The simple fact is that the phone number network is still just too big to fail. However there is no doubt that we are entering a new era for phone numbers. It’s just not one in which phone numbers are dying. They are simply hidden beneath a name and a picture in the contacts lists on our smartphones, an important bit of identifying information that we need not remember for most friends and family.

But we all have one and know it by heart, ready to hand out to new acquaintances and colleagues. So the next time someone tells you phone numbers are dying, remind them that they still have one, and that Elvis made $55M last year.