Ben Smith is the former and founding editor-in-chief of Buzzfeed News, the founder and editor-in-chief of Semafor, and the author of a new book called Traffic: Genius, Rivalry, and Delusion in the Billion-Dollar Race to Go Viral, which is about the rise and fall of the social platform age in media, through the lens of Gawker Media and Buzzfeed and, in particular, their founders, Nick Denton and Jonah Peretti.

I say the fall of the social platform age pretty literally: just before we spoke, Buzzfeed actually shut down Buzzfeed News, saying it just wasn’t making enough money, Facebook and the rest are all in on vertical video, and the chaos at Twitter means a lot of baseline media industry assumptions are now up for grabs. Ben and I talked about a lot – where do journalists build their brands now? Where does traffic even come from anymore? What’s next?

Of course, we talked about Semafor as well. Ben and his co-founder, Justin Smith, raised $25 million and launched a news website, newsletters, and events covering the US and sub-Saharan Africa, with plans to expand into other regions. I wanted to know what lessons from Buzzfeed Ben brought into Semafor and, honestly, how he’s thinking about building an audience instead of just trying to get traffic.