Recently Yahoo unveiled their new Maps product. Most shocking is the new Yahoo Maps is built on an AJAX platform, replacing the previous Flex 1.5 implementation. Why would Yahoo throw away an entire product, an entire investment in Flex technology? Was it because Flex is inferior to AJAX? Anyone who has dealt with cross platform issues with CSS/HTML rendering and differing Javascript implementations would laugh at that notion. The reason Yahoo ditched Flex was simple. Advertising. Advertising on the web is quite mature. There exists a number of players and technologies for serving, tracking, billing and displaying ads on the Internet. Without exception, each are based on serving ads inside HTML. Since usage of Yahoo Maps is 'free' (as in Beer), Yahoo relies on increased traffic to increase ad clicks, thus increasing profit. Speaking from a purely technological point of view, Flex is far superior for rendering and interacting with mapping interfaces. The performance of RIAs running on Flash Player 9 is orders of magnitude greater than Javascript in the browser. Maintaining state is much better done in Flex, than Ajax. That and 50 cents, the old saying goes, will get you a cup of coffee. In this day and age of 'free' applications, there will be advertising. Unless Adobe levels the advertising playing field, Flex will consistently lose out to traditional browser based (HTML/CSS/Javascript) implementations. Adobe, are you listening?