Have you ever wondered what were the interests of the people who Googled you? Have you ever wondered what results did raise their attention, so to which they reacted? Well, there is a way to follow up which ranking the global index gives to your identifier in certain points in time. If you do this regularly, you tend to get the feeling of the trends which results are rising and which are loosing their position. Of course this could be automated too. This way you can make pretty good conclusions on which results your respective audience is reacting to.
Alternatively you can exploit this to find out when someone has been using proxy servers or doing extensive WhoIs and DNS queries to your domain or name, or if they have searched you from various archives and indexes. This is because most of those will publish their search and then google will index it. This never happens by accident or by itself. You have few evidence of course on who did all of those, but its easy guess if you know what is happening around. And even if you could not conclude who, you can make pretty good guesses and use the information, exploit the ranking, anyway!
The funny thing is that as someone tries to hide herself with some extensive applications, their actions are still recorded to the “Unintentional Effects of the Google Ranking“. This is kind of declaring the Google index to be the ultimate global Honeypot!