If anyone remembers back to the days when Mosaic pushed Lynx out of the way, the entry level resolution for "graphical browsing" was 640x480.
For years it remained the same, until 800x600 started to get pushed by Apple, and higher resolutions by PC user went to 1024x768.
Those who redesigned too early for the higher resolutions had to deal with visitor complaints that the information was "chopped off" or the user had to scroll left or right.
I stuck with designing for the lowest common denominator (640x480) for a very long time, and watched as the first PDA's supported HTML.
I've pretty much always stayed 2 cycles behind the bleeding edge -- using a self-centering layout where I knew +90% of users would have no problem viewing my content.
While "cell phones", "smart phones" and mobile apps are "the rage" (today), the truth is you can't read very well on one of them, you certainly can't print anything most of the time, and the data storage capabilities are minimal.
Walk in any office, school, library, government office and you'll find desktops computers -- they aren't going anywhere.
Sure there are plenty of business that have gone mobile, but the one thing they are all looking for a bigger mobile devices, not smaller.
So, we have the birth of the "tablet". It's really nothing different than a laptop, except the screen and guts are all one piece, and the keyboard and "mouse" have been replaced by touch software.
Sales of tablets will continue to rise and "laptops" will fade, (forget netbooks -- they were an intermediary step to sell cellular service and cloud storage and were just pared down "laptops").
I have a very interesting research group to study and base my predictions on -- I'm the parent of a 15 year old.
15 year olds use their cell phones to text, phone, trade photos, etc.. but once they are in the house or at school they go to the desktop, laptop or other large scale device to research homework, type up a paper, browse their Facebook wall, manipulate photos and videos they've captured from their cell phone or digital cameras, use video chat sites like "oovoo" -- they all HAVE TO do their homework on the larger scale devices.
If you want to predict the future of computing -- do a study of 12-18 year old's computing habits.
FWIW -- I haven't heard one of them say "I want a netbook" since the cell providers and the big box retail electronics stores pushed them 2 Christmases ago.
Look for larger tablets this coming "retail electronic holiday season" --- the ones you could do something like "browse websites" on.
The web isn't contracting, it's fragmented between semi-useful mobile "apps" coupled with reduced numbers of people establishing (very) small business websites, small organization websites, and individual's websites since they can just throw up a Facebook page, get a twitter account to promote, upload some YouTube videos to link to and skip the domain names, hosting and other costs and obstacles associated with have "a website"). Any decent size organization will have a website, and Facebook, Twitter, and the rest are websites.
The web will live long and prosper.
[This message was typed on my laptop, which I use a "desktop" with a full size keyboard, a mouse and a decent size monitor plugged into it -- and I can unplug and pick up the laptop and take it with me and have all my software and data "on the road"]