This is covered quite extensively in the podcast, but the quick version is that we went to a PHP conference very early on to exhibit and found something like half the people that stopped by our booth thought GitHub sounded cool and would be interested in evaluating it, but it being a SaaS only product was a non-starter. We decided we wanted to serve all the developers inside Enterprise companies too and started down the long road of figuring out how to make that work. We had no idea how hard it was going to be, but our goal of helping ALL developers work better together meant it was something we needed to figure out.

Give the podcast a listen for more context around that and your other questions!