It's amazing how temporary things are. I never used AIM much but if I had I would have a lot of history in my life with a particular service and now they would pull the plug. Ditto with Facebook these days. Or hosted software like Google Reader.
In contrast, I still have most what I grew up with. Disk images of my old computers, binaries of games and applications, fully usable in emulators. There's IRC -- while the networks I used then have died a long time ago IRC probably never dies. I still use IRC on some networks and interface some other chat services by using a proxy frontend that you can connect with an IRC client.
But most importantly, I can launch early computer games from my childhood. It's like having your old toys on a shelf at your parent's house. Not only I can still try out the game I never could finish (and observe that I still can't finish it because games in the 80's were often both stupid and ridiculously hard), but I can put my kids at the controls and tell them this is what their parent used to play at the same age. It's not just history and culture but an origin. This is where I came from. For a human being that is a very concrete, if not tangible, thing, and of value in itself. Now think that you can't fire up Instagram or Facebook or even Angry Birds in 2035 and tell someone hey this is how we shared pictures, messaged, and gamed back in the 10's.