From Google Webmaster Center:
All of the text that users can see as they interact with your Flash file. If your website contains Flash, the textual content in your Flash files can be used when Google generates a snippet for your website. Also, the words that appear in your Flash files can be used to match query terms in Google searches.

Obviously, this is great news to the web design community that has been scratching their heads trying to circumvent Google’s inability to spider Flash sites. In the past, there were a number of methods for providing <noscript> data for pages and sites built primarily in Flash. The preferred, though marginally successful, method is to create a “ghost site” that provides HTML content extracted from Flash database pages with a meta- or javascript- redirect on the top of the pages. While in theory this was an easy and practical solution, Google Sitemaps and Google-bots disliked spidering through sites with too many redirects as they could be (and probably are) used primarily for hallway sites where the sole purpose was to get more traffic to another site. Boosting your Google rating through hallway sites, according to Google and the chagrin of most web users, is a major no-no. But, nonetheless, it was an effective solution if Google didn’t catch you.

Now, the spiderability of Flash removes this necessity and provides a cleaner, more organic option: don’t crawl the work-around, crawl the site. Their progress is slow, but promising. Take a look at the original article here:

The best part is that Google says you don’t need to do anything to ensure your legacy sites are spiderable by their new proprietary algorithm. That said, there are currently a few limitations:

Q: What are the current technical limitations of Google’s ability to index Flash?
There are three main limitations at present, and we are already working on resolving them:

1. Googlebot does not execute some types of JavaScript. So if your web page loads a Flash file via JavaScript, Google may not be aware of that Flash file, in which case it will not be indexed.

2. We currently do not attach content from external resources that are loaded by your Flash files. If your Flash file loads an HTML file, an XML file, another SWF file, etc., Google will separately index that resource, but it will not yet be considered to be part of the content in your Flash file.

3. While we are able to index Flash in almost all of the languages found on the web, currently there are difficulties with Flash content written in bidirectional languages. Until this is fixed, we will be unable to index Hebrew language or Arabic language content from Flash files.

Sadly, most of our sites are built with CMS systems where content is pulled from XML or a database. But a lot of the main titles and headings for pages and sites are still encoded directly in the Flash. AND you can continue to have links INSIDE the Flash site for “HTML Only” versions (rather than below the Flash) to allow Google to find and crawl them. While this may seem counter-productive (as people that prefer HTML would never see the Flash links to the “HTML Only” sites), Google has no preference and will continue to spider them—thus creating more links to spider.

All in all, this is great news. Thanks, Google. You’ve again made our lives easier and helped us to stop having to fool you with ghost sites.