It's an interesting topic. I'm certainly noticing more bikes on the road than I was in September and October. I would have expected to see less given the shorter days and cold weather.
I think the image of the cyclist itself may be changing. It's probably being seen in a more positive light by more people.
Perhaps, as has been said before, the cycling success in the Olympics played a part. I've also noticed far more bicycles appearing on TV both in programmes and adverts where they are often in the background for no apparent reason but probably to associate the product with something good or green or healthy.
Then there's the recent increases in public transport costs.
Maybe some 5MPH motorists are thinking twice when they see someone pass them on a bike at 20MPH down the cycle lane.