Flash sites are now indexed by search engines!

Historically most search engines indexing algorithm was developed as text based, looking for keywords inside HTML text and links. So the sites created in Flash (SWF) and other Reach Media Technologies that didn’t display their content in simple HTML format were practically excluded from search results.
This situation was frustrating for web developers, who had to find workarounds and alternative solutions like creating text versions of the same pages to help search engines index and rank their Flash sites.

It was not ideal for searchers either, as potentially great matches for their queries were not accessible.
Previously, Google’s help documentation has warned against the use of Flash-only sites:
“In general, search engines are text based. This means that in order to be crawled and indexed, your content needs to be in text format. This doesn’t mean that you can’t include images, Flash files, videos, and other rich media content on your site; it just means that any content you embed in these files should also be available in text format or it won’t be accessible to search engines.”

They have suggested using Flash sparingly or using a method such as Scalable Inman Flash Replacement (sIFR) to provide an HTML source that can be rendered as either Flash or non-Flash.
In June 2008 Adobe come up with a new technology for Google and Yahoo! that allowed their search spiders to navigate through a live SWF application and index it’s content.

How is it done?
The Flash Player technology, optimized for search spiders, runs a SWF file similarly to how the file would run in Adobe Flash Player in the browser as if by virtual user, and it returns all of the text and links that occur at any state of the application back to the search spider, which then appears in search results to the end user.
All of the extracted information is then indexed for relevance according to Google and Yahoo’s algorithms.

The good news also was that all existing content developed in any version of Flash became immediately searchable without the need for companies and developers to alter content.

Limitations:
Although Google can now discover and index text content and links embedded in SWF files of all kinds, including self-contained Flash websites and Flash gadgets such as buttons or menus there are still some limitations:
o Animations and video inside Flash sites can not be crawled still.
o Googlebot does not execute some types of JavaScript. If the webpage uses JavaScript to load a Flash file, it may not be discovered and indexed.
o Although search engine can indicate that the site has indeed contains the information the user is searching for, it cannot take user directly to that content. Clicking on search results will open the site and then user will have to manually navigate through the site to find required content. The same also applies to other reach formats like PDF and makes user experience rather frustrating.

Becoming visible is one thing, actually ranking highly is another. Google currently can find about 73 million Flash files on the Web. But until it becomes easy for the average Webmaster or blogger to link deeply into those Flash files, they are not likely to appear at the top of many search results.

Web developers and SEO still have lots of work to do to optimise Flash sites to ensure that they are not only found in search but usable and accessible enough for users.

For more information check official announcement from Adobe and Google.