Yes. And now it is.
You're playing a game of semantics.
are iPads and tablets "computers" in the strictest sense? Of course they are. But so are toasters and washing machines.
Are they general, programmable instruments? Yes and no. They have their own set of limitations and most of them take a walled-garden approach. For example, it takes expertise to switch your smartphone or tablet to another OS, and even then you'll have myriad issues.
Can they replace the desktop and laptop PCs? For things like facebook and web apps, Yes.
But for the general case? no. The fact is that while a PC can do everything you can do on a tablet or smartphone with a larger screen and better input capabilities as well as more "oomph" you cannot do anything you would do on a PC on a tablet or smartphone.
Google is , has, announcing anew tablet the will out do the iPad.
Just like Google+ was totally going to outdo Facebook.
Sooner or later, the tablet , in some form, will be the new personal computation device you carry on your persona. (See computer news for details)
It already is, but the same thing was said about laptops several decades ago. They are only now serving as reasonable replacements for a desktop PC for many people without sacrificing capabilities.
