Success of iGoogle in 2005 with Mini Web Apps and a Free App Store like System. The Desktop widgets of Yahoo, Google Desktop Search who created a Apps Shop or App Vending Store formed the ideas.
These innovations and rapid Hardware size shrinking, low power chips, flash+, wireless and broadband technology boost have lead to the Tablets you see today,
Chumby Web Computer
I made this post today when many facts feel in place and i came to the conclusion that the Tablets, AppStore manifested from the concepts of touch usability, widgets etc. that came from gadgets like chumby and web services like iGoogle, both are gone today - 2012 delabs