It's amazing that the mining hardware just keeps piling in --
I reckon that a lot of the new miners are just people using equipment that they already had, maybe with a gfx card upgrade or two. They've watched and listened while someone they know has had their computers making money for them, and finally they have decided to give it a go. "Hell, even if it's just a few dollars, a few dollars a day pays for fuel

", they may reason.
That's how I got into it. I'm mining on a PC that I built in February because my old one was about 3 years old and getting dated. The hardware was just sitting there running 24/7 anyways when I stumbled into bitcoins and I decided it was worth it to give it a go. So far my mining proceds have paid for an added video card so even if I stop now I'm still ahead.