The Snapchat logo uses the font Avenir Next
We couldn't find the exact font and it's likely handmade for the purpose of the book, we did find this similar one though https://fontbundles.net/lettersiro/81615-zembood-typeface
Midnights by Taylor Swift used the font Neue Haas Grotesk Display 65 Medium
The latest font Twitter uses is called Chirp. Twitter previously used: Helvetica Neue, Segoe UI and Ubuntu.