I found a synopsis of a talk that a Google employee named Marissa Mayer gave. It was very interesting. There were lots of neat facts I had not heard before. Here are the ones I think could actually be useful.
Google makes changes small-and-often. They will sometimes trial a
particular feature with a set of users from a given network subnet; for
example Excite@Home users often get to see new features. They aren’t
told of this, just presented with the new UI and observed how they use
They use the 20% / 5% rules. If at least 20% of people use a feature,
then it will be included. At least 5% of people need to use a
particular search preference before it will make it into the ‘Advanced
They have found in user testing, that a small number of people are very
typical of the larger user base. They run labs continually and always
monitoring how people use a page of results.
[tags]google, excite, google ui[/tags]