We are so dependent on our cellphones, and they increasingly perform more and more functions for us. They are essentially an extension of our brain. When I was younger I had many phone numbers memorized, I could easily pick up a phone and dial my friends number with no problems. Now I can't dial anyone's number without using my contact directory on my cell phone. Instead of me remembering the numbers, the phone does that function for me.
I also don't have to remember many other things, instead of storing it in my brain I just type it into my extended brain, my iPhone. Remembering things has never been easier. If I need to be reminded of something I just go to the reminder app and I'm reminded to do it.
From the time I was in Jr. High up until my mission I would use something called an alarm clock to wake me up in the morning. After time my alarm clock was replaced by an iHome which allowed my music to wake me up. Now my cell phone has replaced the use of an alarm clock and I no longer have to lug an alarm clock with me if I'm going to need to be woken up in the morning.
I love taking pictures and documenting my life that way. I used to have to take a camera around with me. I got an iPhone and haven't touched my camera ever since. The photos are just as good as if I used my digital camera, and I can easily show people my pictures right on my phone rather than showing them a photo album that I would have had to lug around.
The smart phone has also replaced things such as our daily planners and palm pilots. Our phones are basicall our life lines, without them it would be very hard to function. We check our email, browse, the web, and we can talk to pretty much anyone we desire all around the world.
We are currently trying to even replace our wallets with our smartphones using NFC chips in our sim cards that allow us to use our credit cards just by presenting our phone.
We used to battle about which computer was superior, or what operating system was better than the other. I think that today's battle is which smartphone is better, which phone should I buy, who makes the best smartphone that will fulfill all of my needs.