Google announced their public DNS server today. I'm using it right now. There's been a bunch of speculation as to why Google is offering this service for free but the reason is pretty simple: they want to speed up people's Google search results. In 2006, Google VP Marissa Mayer told the audience at the Web 2.0 conference that slowing a user's search experience down even a fraction of a second results in fewer searches and less customer satisfaction.
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.
Former Amazon employee Greg Linden backs up Mayer's claim:
This conclusion may be surprising -- people notice a half second delay? -- but we had a similar experience at Amazon.com. In A/B tests, we tried delaying the page in increments of 100 milliseconds and found that even very small delays would result in substantial and costly drops in revenue.
Jared Spool reveals that a simple yes/no question added to Amazon's site brought in an additional $2.7 billion in revenue.
Amazon had reviews from the very first day. It's always been a feature that customers love. (Many non-customers talk about how they check out the reviews on Amazon first, then buy the product someplace else.) Initially, the review system was purely chronological. The designers didn't account for users entering hundreds or thousands of reviews.
For small numbers, chronology works just fine. However, it quickly becomes unmanageable. (For example, anyone who discovers an established blog may feel they've come in at the middle of a conversation, since only the most recent topics are presented first. It seems as if the writer assumed the readers had read everything from the beginning.)
The reviews of reviews are really helpful when buying. Personally, I always check out four types of reviews on Amazon in roughly this order:
1) most helpful/highest rated, 2) most helpful/lowest rated, 3) least helpful/highest rated, 4) least helpful/lowest rated
Sometimes reading a really negative review which many people think is spectacularly wrong can help make a useful buying decision.
See also the $300 million button and Cynical-C's new series on one-star reviews of classic books, movies, and music: To Kill a Mockingbird and Sgt. Pepper's Lonely Hearts Club Band. (via designnotes)
Update: There is also the Billion Dollar HTML Tag.
This phenomenon is best illustrated by a single design tweak to the Google search results page in 2000 that Mayer calls "The Billion Dollar HTML Tag." Google founders Sergey Brin and Larry Page asked Mayer to assess the impact of adding a column of text ads in the right-hand column of the results page. Could this design, which at the time required an HTML table, be implemented without the slower page load time often associated with tables?
Mayer consulted the W3C HTML specs and found a tag (the "align=right" table attribute) that would allow the right-hand table to load before the search results, adding a revenue stream that has been critical to Google's financial success.
Profile of Google's Marissa Mayer, Google's answer to Apple's Jonathan Ive. She grew up about 100 miles from me in northern WI.