My experience, here in the states (U.S.A.) was an emergence of any cellphones close to first months of 2004. The smaller package size, and awesum convenience was very novel, and took off rapidly over just a couple of months.
It did take maybe a decade, before you didn't have concerns about using minutes. (Although I didn't use any international). Internet access came slowly, starting with email.
My heavy use of smartphone to play videos was not until at least 2012, (that's 12 years now). That feature has helped with MASSIVE insomnia, being that I'm very Type A, having troubles relaxing and putting work issues aside.
Ironically, it's the more interesting video programs (like science / NOVA), that put me out, when sleep doesn't come.
The smartphone videos came, and the whole DVD movie industry went 'away'.
Pre-2004, virtually all cellphones were huge, walky Talky radios, with long antennas, and perhaps larger than my head. Rarely, I would encounter some friend that had one...they always said; "Don't call...ever, because the billing charge is huge....".
Ironically, the more modern flip phones began occupying a valued place, in big city street 'culture'.
The rise of tablet media brought huge changes, for GPS functions and ebooks.