Interface Trend: Fluid Interfaces

A "Fluid" interface allows you to change the size of your window, and the interface adapts accordingly to show you more or less content -- more or fewer thumbnails for example -- without decreasing the usefulness of the site.

Not only is this great for users who have larger monitors (or smaller ones such as iPhones), but as a designer, it makes it easy to adapt your site to other devices (like cell phones) without having to generate lots of different versions of your design.

Stretch and shrink these windows and notice the number of thumbnails changing:

http://www.thefind.com/search?query=frog
http://www.thefwa.com/

This one takes a little more effort, but it's a nice example in Flash of the interface adapting to window size.
http://www.cubic.com.br/#/en/peca/44/81