I'm a front end engineer at CB Insights. We use d3.js for almost all our visualizations, from simple bar and line charts to complex network graphs.
I wanted to share some of what I've learned but I didn't know where to start. There are a ton of d3 tutorials for newbies out there and I didn't feel like I would be able to add anything new. But after reading Mike Bostock's "Let's make a bar chart", I had an idea: I will pick up where he left off and add something new to the simple bar chart we have at the end of the last part of that tutorial: