Seems to me a lot depends on the age group... the youngsters among us whose vision is clear like to use cellphones and other small device screens for getting on the web (helps them get past mom and dad`s surveillance a lot of times... no wonder). But for those with aging eyes these small screens are difficult at best, and the population in the USA is definitely aging. Since it many times also costs an additional fee for the web connection, this tends to put a small damper on use of the small devices--does for me. But larger businesses demand constant connectivity, so Blackberries have proliferated, at least for email usage, and cell phones are used constantly by teens for text messaging (and probably for cheating on exams as well, never mind all the other things they can do with them). Another thing to think about is video... youtube.com
is immensely popular, but the movies don`t translate as well to such a small screen, if they are viewable at all. Ecommerce sites can be rough this way, too, as one wants to see
more closely what one is buying and the small devices lack in this
area--that tiny screen can only show so much.
Personally, I don`t see desktops/laptops as being obsolete any time soon as a type of Web connection device, but I also feel that the smaller devices need to be considered and kept in mind as the Web continues to grow. This is where simpler sites with fewer graphics and more real content will shine (basically, well-designed sites with something to offer) as these devices develop their technology and continue to be such a strong part of our culture.
An additional note on cellphones.. in other countries--a friend of mine who moved back to Italy tells me this--they are so accepted that they`ve pretty much become the national pastime. No one is ever seen without their cellphone, and they are almost always talking on it. With that kind of acceptance, and the relatively low cost of them compared to computers (often free as an incentive to sign up for a contract) one cannot discount their importance on the web.