Their cell phone is the only computer most people will ever need in the reasonably near future. For some people, it already is all the computer they ever want and more. More of us will join that group with every passing day.
Cell phones are already more powerful than the personal computers of the not too distant past. The barrier will not be the compute power that you can carry in your pocket. If you want to talk about the needed processing power or storage, any level you want to talk about will be in your computer someday.
There are three other hurdles that the cell phone needs to overcome to deliver all of the utility of the modern personal computer. The PC wins today for screen size, keyboard, and relative security, but cell phones already have options that show that these advantages are on the way out. The personal phone in a cell phone is almost on your doorstep in a package that will be hard to resist.
You can already get a cell phone with a projector good enough to put on a quality presentation. It won’t be too long before we see a cell phone that can project a screen of almost any size that creates a clear, sharp image in full daylight. At this point, the cell phone will have display capabilities that at least rival the capabilities of a desktop PC.
Already lots of phones provide the capability to plug in a standard keyboard. The only barriers to be hurdled here are design problems with the keyboards themselves. So far, none of the keyboards that you can carry in your pocket can really deliver the feel of a quality keyboard. That will happen soon for those of us that cling to the need for a keyboard.
For those who are looking for another means of input, voice is coming of age. It works somewhat on Windows mobile phones, and it seems to work very well on Android phones. I haven’t seen this on iPhones, but I suspect they are better at voice recognition just like I assume that they are better at everything else. They all seem to be better at voice commands than voice text entry.
The worst security feature of cell phones is how easy they are to lose. I don’t think we can fix that problem, but we can change the impact of a loss. First, we can have an automatic backup system where all of your data is kept on a secure server somewhere. I believe that Apple’s Mobile Me does that, and there have to be many competitors. These services will get better and better.
It seems like you also need the other side of the coin. That is, you need to be able to erase your phone remotely when it is lost. Some phones may have this already. It certain