I'll have to agree with Russell on this: Mobile Web is 19% of PC Web.

In fact, 5.7 million people in the UK use the mobile web, as opposed to 30 million who access the web by PC. This means that the mobile web is already nearly one fifth the size of the PC web.

In the US, the stat is 17% (30 million of 176 million), which is pretty impressive considering that the US often lags behind a little in mobile. It's also worth combining these two pieces of the jigsaw and saying that there are as many mobile web users in the US as there are PC web users in the UK.

Having recently stopped work on a mobile social network and seeing the number of people who rapidly caught on and used the service (and were obviously using other similar services on a regular basis), I've seen the growth that can happen, and the way the mobile web is being adopted not necessarily by the same people who are early web adopters, but by people who may not normally have or be interested in PC-based Internet access.

Accessing the web via the mobile, as any sane, thinking person must acknowledge is going to dwarf PC access. And indeed, I would argue that it'll replace it altogether within the next 5 years - PC style functionality (keyboard and large screens) will be available via a docking station when you need it. So this is just the start of things and as fixed price data packages become available, handsets get better, speeds get faster and mobile sites are better designed and optimised, the pace of growth is simply going to explode.