I have written a few times bout the problems with putting flash on your site. It’s cool, and it’s sexy, but search engines want text rich sites, and movies and text rich content don’t mix. Recently, I came across a site that did a really nice job of talking about this issue, and that also provides some great Flash implementations tips if you do plan to put Flash on your site. Here are some of the key concepts:
As stated before, if you are building Flash sites professionally, you probably move all your content out of your Flash movie and into an XML file or keep it in a database. This makes it much easier to allow Google to index this content by using progressive enhancement.
The article then goes on to provide a specific coding example for an implementation. If you are planning to use Flash, this is a very good way to go, and it will allow you to provide search engine indexable content, while still having your Flash.
Basically, it works by providing HTML content to users who do not have a Flash player (or the correct version thereof). This almost sounds like cloaking, but the two things should not be confused. Your HTML needs to be on the same topic as what is contained in the Flash.
In any event, sites that do not follow this guideline are not going to get very many links any way. And they certainly will not prosper in a world where user personalized search algorithms will play a large factor in results.