SEO and File Extensions

The most common questions of SEO's will be, Is it important from SEO point of view what kind of extension has page html, asp, cfm, php … Can it make your web site pages be more visible on search engines with a specific extension or not?

Many of us are familiar that shouldn’t build websites using Flash and JavaScript, coz Google can't read it. It looks really cool, but Google will never find such websites.
I got an explanation from one of the expert, follows.

The extension is irrelevant to Google, but it is very relevant to the workings of your site. .html is what Google actually sees and reads, but PHP, ASP and CFM are all made to output html. The real difference lies in the technology. ASP is a scripting language also unstable and not secure. CFM or ColdFusion is a Windoze application, so it runs a Web server application on top of Windoze. It can also be a bit expensive to license depending on the demands of your site. PHP is free. It can run on Windoze, but why. It actually runs as an extension of Apache. In that environment, it is very stable and very fast. A LAMP (Linus/Apache/MySQL/PHP) installation is a common platform to use, but I prefer to run Apache, MySQL and PHP on an OpenBSD server. OpenBSD is by far the most stable and secure platform around. Linux will be fine for many applications.