How Do We Adapt to Things?

We've discussed cultural evolution, and everyone knows about evolution by natural selection, but is something different happening now? Some people have said that we have transitioned to a different a third type of evolution, memetic evolution. Is this just an improvement to cultural evolution in the same way that cultural evolution was an improvement on genetic evolution? Or is it an entirely different beast? Does it allow us to adapt faster? Or does it make all adaptation more difficult?