It means that Blink will be to WebKit what WebKit is to KHTML.
KHTML is still being maintained, and code is regularly ported from WebKit back into KHTML.
But what kind of new features originating from KHTML continue to be ported into WebKit? If nothing new from KHTML is worth porting into WebKit while new features of WebKit are being ported back into KHTML, then KHTML really is just a perpetual, previous-version snapshot of WebKit.
As somebody who doesn't consider closed-source software the bane of computing, I personally like the idea of open source products having some measure of "reinventing the wheel" as well having to compete with each other as much as is the case with closed source products. However, I don't understand how a dyed-in-the-wool proponent of open source can think what happened here is a good thing.
Remember that Apple did huge things to WebKit to advance their own agenda, mostly in ways that enable WebKit to be used to create aesthetic and fluid user-experiences - whereas Google's main motivation seems to be performance.
How much innovation in the area of aesthetics and "fluid user-experiences" have been added to WebKit by Apple since Google essentially took over all of the performance innovations? It seems to me performance has a lot to do with "fluid user-experiences" anyway.
Open source projects need *somebody* to push an agenda, or these projects die on the vine. WebKit no longer has anybody to push an agenda.