One of the occasionally annoying things about developer communities is their tendency to present certain technologies as unqualified 'magic' and one should be thankful for developing for platform x because only it has technology y. GCD is sometimes presented this way, when it's mostly just a thread pool with a nice API.

Which is why articles like this are so great. When I was first dipping my toes into development, Mike Ash's articles were a great help in cutting through the marketing hype and realising that these are mostly things you could have implemented yourself given the time and inclination.