[at-fates-hands]

How many of these were companies acquired by Google, and then dismantled after the project didn't gain traction?

Not bashing Google, but there's always posts on Medium about how some startup got bought by Google, promised they wouldn't change anything and within a few months, simply dropped the project and laid off the employees.

[gwern]

Some, but while being an acquisition is a small risk factor, Google is pretty ruthless about killing its own stuff as well. In my dataset from 2013 ( http://www.gwern.net/Google%20shutdowns ) there were 63 acquisitions vs 287 internal products, and being an acquisition increased the odds of death by an OR of 1.13 (small and not statistically-significant).