Was this review helpful to you? MAR 20 2009
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.
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.