Clearly, access to the Internet from mobile devices is increasingly rapidly, from smartphones, lower-end featurephones and (depending on your definition) notebooks/netbooks.
As I've written about many times before, there's a huge debate about whether the future of the web lies in the mobile domain, or whether it will remain PC-centric.
Usually, the example that gets held up by the mobile fraternity is Japan, which clearly has been in the vanguard of wireless Internet adoption since the early days of i-Mode. The interesting thing to see is that in fact, most people in Japan use BOTH mobile and PC access. About 4% even use TV or game consoles as well.
The chart on Page 3 of this document from the Japanese Ministry of Communications is probably the most clear representation I've seen. I'll be interested to see what the end-2008 numbers look like, as there will undoubtedly be more mobile phone users, but also more people with netbooks and other mobile-broadband enabled notebooks. That said, the 3G dongle phenomenon doesn't appear to have been as broadly popular in Japan as elsewhere.
Of course, Japan could arguably be treated as an exception rather than an example -it is *different* to most markets in many ways. The operators control handset architecture & capabilities much more tightly, it was a very early adopter of 3G, and everyone is on poast-paid data plans with easy access to data. On the other hand, PC Internet is much more attractive as well, with ultra-fast and cheap DSL, and rapidly rising penetration of fibre to the home.
Looking at the stats, I wonder if the asymptote, for a country with affluent population and fantastic mobile and fixed networks, looks something like 15/70/15 . That is, 15% are mobile-only Internet users, 15% are PC-only, and 70% use both.
As I said, I'm hesitant to hold up Japan as an inevitable end-point for other country, because much of the technology market is pre-defined by "historical accidents" like government policy, specific operator strategies, or early PC/mobile uptake shaping users' behaviour.