My first PC had a 286 processor with an EGA display and a 40mb MFM hard drive (and, let me tell you, those were some MEGA bytes). That glorious gray, metal box first sat on my desk somewhere around 1985. And, you know what, I was still using that machine -- with some significant modifications -- until 1997. That's 12 years of using, and enjoying, the same machine.
Compare that with smartphones, where I have a really hard time making it more than a year before I get "the itch" to upgrade to a new model. (And I tend to upgrade less often than most of my friends and colleagues.) The difference in longevity between my PCs and my phones is due entirely to modularity and upgrade-ability.
When I first got that 286 PC, for example, it had no sound card, just a PC speaker that could beep and squeal at me. But thanks to the modular design, I was able to drop in a SoundBlaster card some years later, followed by a VGA card and monitor. Then an IDE controller and a bigger hard drive. Eventually, I even upgraded that beast to a 486dx-66 processor and kept all of the other components in place.
It was cost effective, convenient and...fun. My PC was my own. I didn't put the original machine together (we bought it pre-assembled from a small computer shop) but, by the time the 1990s rolled around, I had so heavily customized and modified it that the beast was one of a kind. And it suited my needs perfectly.
My current phone, on the other hand, doesn't really feel like my own. Sure, it's nice enough. And technically I can extend the storage with a little micro SD card. But otherwise there's nothing I can really do to it. Built-in storage, RAM, CPU, GPU, screen, camera, inputs/outputs (such as USB or HDMI ports)... it's all locked.
So, as you may have guessed, I am practically giddy with excitement over the possibilities of Motorola's Project Ara and Phonebloks. To have a highly modular phone system that I can tweak, hack on and otherwise fiddle with until it is a unique machine that is truly my own? Yes, please.
Now, in order for this to really be amazing, there will need to be an active community and a strong ecosystem of components. Luckily, Motorola has made a few statements about its open source approach and interest in working with the community. So I am optimistic.
Now, I just hope I can get my hands on some Projecta Ara-based hardware before I feel the need to upgrade my locked-up, monolithic phone...