Today, a lot of websites employ flash animation products from companies like Adobe. Basically flash animation gives webmasters the ability to include small animated vectors into their web pages.
Of course, these animations have some influence on the way your site is "seen" and indexed by the search engines. The problem of Flash Search Engine Optimization arises, which is a very serious matter in terms of conversion and web site profitability.
What Are Flash Animations?
Flash files carry the extension .fla. For example a file might be named banner.fla where the .fla represents the flash format extention. The file will then need to be exported into a Shockwave Format (extension .swf) for use on the web page.
Any text that you include in the animation probably won't be indexed by the search engine as they rarely give attention to these formats. In spite of this there are search engines (Google, dir.com etc) that are able to read the text in these http://www.flashtuning.net/. The result is that any site or webpage that is built entirely in Flash will be invisible to the search engines which index only text content in html format.
Why Do Some Webmasters Use Flash
It is not a secret for anyone that search engines don't really like sites that are built using Flash exclusively. These sites rarely contain enough relevant text to allow a good indexing. Above that, not all spiders can read the content of a .swf file. Flash is used though every now and then for mini-sites or for campaign sites.
Here are a couple of reasons people find Flash worth the effort.
It maximizes the animation's impact, which is appreciated in the Internet interactive and visual environment.
It can be combined successfully with other technologies (e.g. PHP, MySQL, XML, images, video, sound, etc.). It is therefore perfectly possible to create a dynamic web site in flash that also has content.
Pros

More content can be added to a smaller sized space without undue compromise of the layout.
http://www.flashtuning.net/ makes it easier to include slide shows and movies into a website.
It is a great tool to create banners and ads, and even Flash videos.
For creating visual impact and drawing the eye to specific points of interest on a website Flash is the tool of choice.
Cons
Sites utilizing flash could take some time to load and it increases bandwidth consumption.
Most search engines don't like and don't index Flash.
Modifying Flash websites can be costly if you use third party developers. This is because they may code the project in such a way that it will be difficult to make changes on your own. To get your changes made you will more than likely need to pay an extra fee.
The "Back" button is usually disabled for flash websites and also Google's AdWords won't approve pages that have the Back button disabled. So, beware of this if you intend to promote your web site by using a PPC campaign.
Flash doesn't care about the visitors' needs - movies that seem endless- sounds that you cannot turn off they will drive your visitors away.
Splash Pages will reduce your visibility in the search engines especially if there is insufficient text on the site that can be used to identify the keywords associated with your products and services.
It is not an easy task to optimize flash for the unpredictable search engines. The amount of time and energy it takes for SEO for Flash websites is far greater than the efforts required for an HTML site.