If it seems like there have been a lot of "birthdays" announced here lately, it's because Apple used to announce a lot of new products in January around the time of Macworld Expo. One of those products that I was present to see the introduction of was the MacBook Air, which Apple introduced on January 15, 2008 (it wasn't available in stores until January 29 of that year).
As accustomed to ultra-thin laptops as we all are these days, the original MacBook Air was a total shock to the crowd at the introduction. How could Apple jam a Mac into such as thin device? I recall leaving the keynote address and immediately running to the show floor to see the MacBook Air for myself, then pre-ordering the 13.3-inch model.
That MacBook Air did a lot of traveling, as I was teaching business analysis classes around the country at the time. During the first year I owned it, it was fun to see just how many people would come up to see how thin and light it was, and how many of them said "I'm dumping my Windows laptop for one of these." I think the MacBook Air was part of the reason Apple is still enjoying growth in the Mac market while the rest of the PC market withers away.