Originally Posted by QuadsZilla

It has no effect for .html or .htm vs. directory in google. However, dynamic extensions like .api or .php could have a negative effect. Also if you have a numbers in the url it will have a slightly negative effect. A question mark in the URL is a big no no.

In msn, it's better to have just relevant keywords in the url with as few other characters as possiable. That's why i like to use the directory structure.