From the web page:

"Have you found a really neat web site that does not rank highly on Google yet? Sure, there are many ways that you could tell other people about it (e.g., add a link to it from your web page, give it a "thumbs up" on StumbleUpon, mention it in a newsgroup, etc).

But why not make such a recommendation as part of a game where your score will depend on the actual Google ranking achieved by the site in the future? Why not find out who is the very best at predicting which sites people will like and that will rank higher on Google as a result?

And why not also make predictions about web sites whose Google ranking will likely go down in the future?

The Speculative Search Game allows you to make such predictions in a competitive environment."

Speculative Search Game (Google Game)