A lot of Web pages are today created with animations made in Flash format, imagined by Macromedia (http://www.macromedia.com).
 
The Flash technology allows, in a quite simple way, to insert animated images and small vectorial animated drawings in your Web pages. Unfortunately, these animations affect the referencing of your site.
 
First, let's see how is structured a Flash file. When you create an animation, you obtain a file, named, for example, anim.fla (the "fla" extension is characteristic of the Flash format). To publish this file in a Web page, it is necessary to export it with the format Shockwave Flash (".swf" extension). It is this file, once exported, which you will use for your Web site.
 
If the animation contains text, it will not be taken into account by the search engine which does not index this format. A page (even a site!) entirely realized in Flash will thus pass quasi unperceived for the search engines, which index, for the majority, only textual contents within the HTML format.

But the file HTML file which "launches" the Flash animation will be indexed.

In this case, you do not have really the choice: you will have to use in the most optimized possible way the <TITLE> tags, the <META> tags (although the Meta "Keywords" tags are not very important for search engines right now, but the Meta "Description" tag still has a certain importance) and, in our case, <NOEMBED> tag (in the same way webmasters employs <NOFRAMES> tag for a site conceived with frames). In the <NOEMBED> tag, try to insert text as much as possible (without spamming, i.e. without abusive repetition of keywords), which is indexed by the spiders of the engines. Another possible field: option "ALT" of the images, if your file HTML contains some.
 
If your site is entirety in Flas format, you can optimize the only pages HTML presented, while waiting for that all the search engines can read the text of Flash animations.

It is largely advised to propose on line an HTML version of your site, with a link to its homepage... which is not included in a Flash animation: -)

Lastly, there is another way for well ranking a site in Flash on the search engines: to pass by the offers of advertising positioning of, for example, Google and Overture to be certain to be at the head of list. Major disadvantage: your have to pay for that :-)

Anyway, always retain an essential point: a spider (thus a search engine) can only read HTML code! The contents of a Flash animation in are thus banished (except, once again, for the engines which can read the Flash). Perhaps that some day, all the search engines will read the Flash without problems. For the moment, it is not yet the case...