They can look great and use a lot of cool elements that you don’t see on other sites. Then again, there are a lot of limitations to an all-Flash site.

Flash sites aren’t good for your search engine optimization, and they’re not very accessible to a variety of users and devices. It’s true that there are Flash improvements in the wings, but when it comes to all-Flash sites right now, proceed with extreme caution.

I thought Google and Yahoo can read Flash content now…

Last year, Adobe announced that Google and Yahoo! would begin to be able to index standard Flash content. Before then, there was no way that the search engines could “read” the information on your site without significant workarounds. Problem solved, right?

Hang on. Depending on how you or your designer has built the site, your content might still be unreadable by the engines or your important keywords won’t be weighted as well as if your site was built with HTML and CSS.

…and it works on my phone, right?

Not exactly. Many mobile devices do use a version of Flash that’s not a full-fledged player. However, if you’re on an iPhone, you browser won’t show Flash content at all. Eric has a great post about mobile phone technology and its impact on business.

And one final note on general usability:

Users who utilize screen-readers or have Flash content blocked for whatever reason cannot read the content on your site unless you take many careful steps to ensure high usability.

So, can I use Flash at all?

Highly recommended. Flash elements on your site are really nice because they keep your customers engaged. They also tell a compelling story.

In general, when you’re thinking about an all-Flash site, there are a lot of variables to consider. This may not be the case down the line, but for now, an all-Flash site isn’t the most usable option for your audience–when they’re looking for you and when they get to your site.