Google Instant Previews is the latest addition to the Instant Search family from Google and it hates Flash.
Similar to oil and water, Flash and search do no play well together. There are many best practices to try and optimize Flash content for search but when it comes down to it, avoidance is the best policy. Instant Previews does not break that mold but further solidifies that Flash will not play well with the search engines and your site will be worse off for it.
This issue comes to light when your whole page is enclosed within Flash. Here is a good example:
Yikes. Now that is a user experience that will not be drawing in flocks of search visitors.
If this is happening to your site because you largely use Flash, there are two ways to avoid that dreaded puzzle piece. First, stop using Flash; it is not as awesome as you think it is. Second, you can block the preview by using the NOSNIPPET tag. It is a meta tag that looks like this <meta name=”googlebot” content=”nosnippet”> and instructs Google to not display a search snippet for your results. Since the Instant Preview is tied in with the search snippet, this meta tag will disable previews for your site. This what you will be serving search users instead:
So, would you rather have no preview or a puzzle piece?
Or, even better, place actual content there and your preview will work just fine.