Update: Dyn says services were restored at 9:36 A.M. Eastern time, and I can now connect to the affected websites again—which indicates the two events were indeed related.
Update 2: Dyn says it was hit with another DDoS attack at 11:52 A.M. Eastern. Currently, Twitter, Etsy, Spotify and the other sites affected by the earlier attack are offline from my location in the Northeast U.S.
Every morning, I sit down at my PC with a cup of coffee, crank some tunes on Spotify, and scour r/techsupportgore for gnarly PC disaster pics to tweet out. Not this morning, because it appears a massive Distributed Denial of Service attack targeting DNS host Dyn has knocked a big chunk of the Internet offline Friday morning.