Hi. I got some (more) questions that I'd like to know before I buy a tablet. 1. Is there a good reason that smartphones are so much more popular than tablets? I mean, I personally think tablets seems MUCH cooler (and more useful) than a smartphone. Is there anything a smartphone can do that a tablet can't? 2. Is it possible to upgrade a 3g tablet to a 4g one, by changing a card or something? Or is it builth into the tablet? 3. Is it possible for tablet developers to garantee that their tablet will be able to do x number of OS upgrades, or does that depend on how the new OS is designed? 4. Say that a new, better type of battery was invented. Do you think it would be possible to replace a tablet's battery? Or the processor? TYVM for any help.