At any rate, every now and then we stumble across a site that's done something Flashtastic (there we go again! coin, coin, coin) and we felt it was only fair to the Flash developers of the world if we took a moment to point those out too. Make your way immediately to the amazing  Get the Glass site, latest volley in the Got Milk? campaign, and help those desparate Adachis pilot their plumbing van to Fort Fridge to secure The Glass. The site is anything but quick to load, but the thought of molasses made me yearn for a nice cold glass of milk which may have been part of their diabolical marketing plan all along. Many kudos to Swedish firm North Kingdom, who beautifully crafted the experience.

(and a hat tip to Coudal Partners for the link).

1. Flash isn't indexed by search engines. As Patrick points out, Google (and other search engines) don't index the contents of Flash movies. Making your site inside of Flash is like saying that search engine traffic isn't important to you - and I've almost never encountered a site for which that is true (it's definitely not for real estate sites!) There are ways around this but most of them are frowned on and one - presenting a so-called 'doorway' page that delivers an alternate text version of your site when the GoogleBot stops by to index - got BMW and Ricoh's German websites delisted from Google (which is a lot like disappearing from the web). It should be possible to use JavaScript (or a similar technology) to detect whether the Flash plugin is installed and to redirect to an HTML-based version of the site if it isn't, and most search engine bots probably don't report having Flash installed, and they probably won't penalize you for redirecting for all non-Flash visitors rather than just them, but then you're just paying more to build a Flash version and the HTML version you should have built in the first place :).
   
2. Flash breaks the Back button. When you're inside of a Flash movie, the browser still thinks you're on the first page that loaded (i.e.: the one containing the Flash movie and not a frame inside the movie) and so Back will take you to the page before the one you're on (i.e.: not the one with the Flash movie). Back is the second most often used browser control (after links) and jumping out of your movie will annoy your visitors every time they try to use it. It is possible to build Flash movies that use the Back button (see Flash Magazine's Making the back button work for Flash), but it's rarely done (and even less rarely done properly).
   
3. Flash doesn't print. When site visitors print the page containing your Flash movie, they will almost always see an empty rectangle where your beautifully styled movie used to sit. It is possible to make Flash movies that print (see Peach Pit Press' Flash MX Printing sample chapter from Certified Macromedia Flash MX Developer Study Guide), but it's a time consuming extra step that most designers don't consider. I wish it were the case that people never printed off the web, but we know lots of people who do, especially when considering buying a home and wanting the ability to print off different models to show their friends and family.
4. Flash movies have a single entry point. You may have the best looking, most original, all-singing, all-dancing Flash production in the history of the Interweb, but people can only enter from the very beginning. There's no way to bookmark a page inside of your website (e.g.: I can't return directly to the unit I'm thinking of buying), and there's no way for me to send a link to a friend (e.g.: Hey honey! I found our perfect new condo, but you're going to have to navigate through this really complicated Flash movie to find it). For the record, there are some techniques for enabling bookmarking inside of Flash, but they seem to be PC only (e.g.: see Bookmarks in Flash!, although half the comments are spam).