I accompanied my girlfriend yesterday night, enjoying dinner and coffee with two of her close friends. Inevitably, since girls will be girls, the conversation turned to relationships.

An interesting question was raised: do you still remember your ex's number by heart? While my girlfriend's friend admitted she did, I suddenly realized that, even as I tried remembering, I really had no idea what my ex's mobile number was.

That made me think: are our personal, internal phonebooks indicators of who's really dear to us? Obviously, I know my girlfriend's mobile and home numbers like the back of my hand. I'm sure you know your significant other's contact info, mostly to the point that you rarely look for their numbers on your phonebook, since it's just faster to type in the number and press call or send.

I'm a pretty forgetful person, and my memory has room for only so much data. Naturally, it only retains what's really important to me. That's why it feels good to realize that I do know my girlfriend's numbers by heart, and that I can no longer recall my ex's contact info.

What about you? Perhaps the way we use our smartphones and PDAs is a great indicator of who we are? Especially since we use them as extensions of our personal lives.