Web page extension issues?

using custom p[age extensions

[bouncybunny]

I am using a blog/content manager to generate pages for as site of mine.

I have decided to rewrite the urls. The default setting ends all urls with the following structure domainname/directory/name/somethingorother

But I wanted to differentiate actual articles, from subject topics - essentially to simulate the difference between directories and pages.

So I have rewritten the articles pages to end with a simluated page extension domainname/directory/name/somethingorother.html

But instead of .HTML I am considering using a different extension for example .PERM to indicate a permalink (or whatever). For example domainname/directory/name/somethingorother.perm

So, my question is, will making up this file extension cause any potential technical or usability issues with any browsers (or even search engines)? Or should I stick to HTML?

Any thoughts?

Thanks

[henry0]

Discussed HERE [webmasterworld.com]