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 The Root of All Evil
======================


A quote from the book _Measure What Matters_ by John Doerr,
quoting Cristos Goodrow, VP of Engineering for YouTube:

"In September 2011, I sent a provocative email to my boss
and the YouTube leadership team. Subject line: 'Watch
time, and only watch time.' It was a call to rethink how
we measured success: 'All other things being equal, our
goal is to increase [video] watch time.' For many folks at
Google, it smacked of heresy. Google Search was designed as
a switchboard to route you off the site and out to your best
destination as quickly as possible. Maximizing watch time
was antithetical to its purpose in life. Moreover, watch
time would be negative for views, the critical metric for
both users and creators. Last (but not least), to optimize
for watch time would incur a significant money hit, at least
at the start. Since YouTube ads were shown exclusively
before videos started, fewer starts meant fewer ads. Fewer
ads meant less revenue.

"My argument was that Google and YouTube were different
animals. To make the dichotomy as stark as possible, I
made up a scenario: A user goes to YouTube and types the
query 'How do I tie a bow tie?' And we have two videos
on the topic. The first is one minute long and teaches
you very quickly and precisely how to tie a bow tie. The
second is ten minutes long and is full of jokes and really
entertaining. I'd ask my colleagues: Which video should be
ranked as our first search result?

"For those at Google Search, the answer was easy: 'The first
one, of course. If people come to YouTube to tie a bow tie,
we surely want to help them tie a bow tie.'

"And I'd say, 'I want to show them the second video.'

"And the Search cohort would protest, 'Why would you do
that? These poor people just want to tie their bow ties and
get to their event!' (They were probably thinking: This
guy's insane.) But my point was that YouTube's mission was
fundamentally divergent. It's fine for viewers to learn
to tie bow ties, and if that's _all_ they want, they'll
choose the one-minute manual. But that's not what YouTube
was about, not really. Our job was to keep people engaged
and hanging out with us. By definition, viewers are happier
watching seven minutes of a ten-minute video (or even two
minutes of a ten-minute video) than _all_ of a one-minute
video. And when they're happier, we are, too."