While I don't necessarily agree with everything in this post, I do see two problems with phone numbers:

1. Ask yourself, how many phone numbers do you actually know at this very moment? I'm willing to bet, on average, it's less than five. It might be slightly higher on this site, but for the average consumer, I'm guessing it's between 1 and 3. I ask people this all the time, and I know many who don't know a single number other than their own, or their parents.

2. You've all seen the Facebook groups that pop up when someone loses their phone. "I lost my phone, give me your number!".

Apple is doing a very good job of solving this for the masses right now with iCloud, but you have to be an iPhone user to take advantage.