It's interesting that the author didn't mention the "full circle" nature of this development.
Qt is the toolkit of choice for the KDE desktop. Back in the day KHTML was a library that was used for HTML rendering in KDE and which made had several Qt classes etc. Apple forked KHTML to make WebKit and KHTML kinda dies a slow death. Qt have now ported WebKit back to Qt (thanks to a more open Apple in recent times it seems). This now means that KDE4 will have WebKit which means KHTML has gone full circle via Apple to get to KDE4.
I notice it's already been put to good use in Amarok 2 development version :)