Twitter. Unquestionably designed to maximize usage, with all of the cognitive tricks some of the most clever scientists have ever engineered. I could write a whole book about Twitter. The tl;dr is that I used Twitter for all of the above (News, Work, Stock) as well as my primary means of interacting with other people/”friends.” I didn’t often consciously think about how much it messed me up to go from interacting with a large number of people every day (working at Microsoft) to engaging with almost no one in person except [my ex] and the kids. Over seven years, there were days at Telerik, Google, and Microsoft where I didn’t utter a word for nine workday hours at a time. That’s plainly not healthy, and Twitter was one crutch I tried to use to mitigate that.