Marissa started with a story about a user test they did. They
asked a group of Google searchers how many search results they
wanted to see. Users asked for more, more than the ten results
Google normally shows. More is more, they said.
So, Marissa ran an experiment where Google increased the number of
search results to thirty. Traffic and revenue from Google
searchers in the experimental group dropped by 20%. Ouch. Why?
Why, when users had asked for this, did they seem to hate it?
After a bit of looking, Marissa explained that they found an
uncontrolled variable. The page with 10 results took .4 seconds to
generate. The page with 30 results took .9 seconds.
Half a second delay caused a 20% drop in traffic. Half a second
delay killed user satisfaction.
If a half second difference made people search less on Google, imagine how much less people are using Siri given that its response times are often multiple seconds long. I think the single biggest improvement Apple could (and really must) make to Siri is to make it faster. And that’s exactly the sort of thing Apple has never really shown the chops for.