Here is a quick video I did this morning using the very cool tool Gource. The video shows all the commits (1265) that were made between release 1.6 and 1.7. QGIS 1.7 was released on 19th June 2011 but there was still some clean up in the 1.7 branch paste that date into September.
It’s interesting to note the large burst of activity around November.
Nathan Woodrow 
I don’t really understand it, but it looks awesome!
It’s simply beautiful :) Thanks
I guess that’s the “Hackfest burst”. Nice work!
Ahhh that’s what it would be.
it’s organic!