This post by Steve Rubel has me thinking, though:
Here's what this means: no two people will see the same web. Once a single search would do the trick - and everyone saw the same results. That's what made search engine optimization work. Now, with this, everyone is going to start tweaking their searches in real-time. The reason this is a game changer is feedback. When you get feedback, you change your behaviors.
I'm not sure that I agree that this means the death of SEO - but it does mean that a lot of the rules just changed again.
But then, they keep changing, don't they? I keep hearing the same set of rules I heard four years ago mindlessly parroted in "how to blog" or "10 SEO tricks" articles, and none of them make the slightest allowance for all the changes to the algorithm that Google has implemented in those years. And there have been a lot of changes.
I suspect, as ever, the gullible will continue to lap up SEO "pixie dust" advice, while the rest of us will get on with making our content as findable and shareable as possible...
Update: The Google Webmaster Central blog already has some thoughts on how Google Instant will affect traffic.