I had a very similar idea, except the machine you're referring to here is your phone. Once you restrict yourself to text and low-res pictures, your phone can be

I had a very similar idea, except the machine you're referring to here is your phone. Once you restrict yourself to text and low-res pictures, your phone can be your server. A single app would let you edit your profile and post items to a feed. This includes a web server. You can also use it to view friends' profiles and chronological updates from their feeds. All data lives on your phone, fetching updates happens by one phone connecting to another phone. Downsides are that it probably needs some kind of centralized discoverability/listing. Bandwidth would be a problem for folks on crappy data plans, but maybe not so much - you're only serving text and low-res pictures to several dozen people. You can also do stuff like waiting to respond to requests when the phone goes on wifi.