The concept of the HTC Tube will likely be the next step in smartphone evolution, I predict. Presently when buying a new mobile, you can only choose one memory capacity (whether it be 8GB, 16GB etc.). With this phone however, you buy the one device and then can purchase cartridges with interchangeable memory!
If you bought the phone and realize 16GB just wasn't enough, simply purchase a 64GB cartridge, slide in the mobile, and away you go! That is the beauty of the HTC Tube. As memory becomes cheaper and cheaper, it only makes sense to start marketing phones in this way.