Google Mail, Yahoo Mail, Hotmail and now Goowy Mail. Goowy mail is a Flash based email client and it is currently in beta. I used to be a big fan of Flash a while back. I even made a number of all Flash sites myself a few years back. This was all before I found out about CSS design, accessibility, usability, etc. I no longer view Flash the same way.
For one thing, I dislike websites that are created entirely in Flash, especially when there is no need for it. What do I mean by a need? Well, take this goowy email site. There really isn't any need for it to be created with Flash. Flash, in my opinion, should only be used when a static image or text doesn't properly convey your message. Good use of Flash would be for guided tours, photo galleries (mainly because it makes it harder to "steal" images), video/audio players, etc.
As you can tell, I'm not too impressed with this Goowy application. If their only selling point is the fact that its in Flash, then I'm afraid its only going to impress a few people and only for a little while. Once everyone realizes that its just another email application, they won't care if their page transitions are fluid or that their menu items make cool (or annoying) clicky noises. In the end, its how functional and useful the site is and not what technology was used to create it.
For now, I'm pretty happy with Gmail. It serves its purpose and I use it regularly. If Goowy mail can promise me near 0% spam and a nice way to organize my contacts and emails, then I might give it a try. If they are trying to impress me with eye candy, then no thanks.