If you've read his book and like it, please go to the site and vote for it (or for the book of your choice).
If you haven't read his book, now is the time to buy it so you can decide whether to vote. Just kidding. To be honest, if you're a tester or a programmer responsible for an application that has to scale and accept unpredictable numbers of queries, you'll find Ian's book valuable. Not only does he take you step-by-step through the process of performance testing--with convenient checklists--and cover the general tools you need, but he deals with "soft" issues such as getting buy-in from management and ensuring resources won't be snatched away at critical moments.
The ATI nomination is just the latest in a string of good feedback that we and Ian have received on it. Congratulations, Ian.