Github devs: this is a sign that pretty though it may be, something is wrong.

cpach · on April 9, 2012

I agree that this should spur the Github developers to re-consider their current design, but I see nothing wrong with the general concept of using URL:s for navigating, just as I prefer the Unix shell over GUI:s for many tasks.

Jakob Nielsen wrote about that over ten years ago: http://www.useit.com/alertbox/990321.html - I think the gist of his article still holds true.