If you're into #FLOSS development and open social networks, I definitely recommend listening to "The Birth of Instagram" on the TechStuff podcast:
There's a load of inspiration in this, both about how startup culture in the Silicon Valley works, about how services such as Instagram managed to get as big as they are today, and what kind of ideas drove and still drives them (in terms of features and product idea). Worth checking out.
The social network of the future: No ads, no corporate surveillance, ethical design, and decentralization! Own your data with Mastodon!