HOW TO CHOOSE A URL

There are two types of urls a static url and a dynamic url. In dynamic url instead of changing information in the HTML code, the data is changed in the database. whereas in static urls contents of the web page stay same unless the changes are hard-coded into the html.
Search engine doesn't like dynamic urls.

The dynamic URL generated for the content looks like this:

http://www.seo.com/forums/thread.php?threadid=12345&sort=date

Whereas a static URL which doesn't change looks like this:

http://www.seo.com/forums/the-challenges-of-dynamic-urls.htm

A search engine wants to index only that pages that are unique. So Search engines decides to combat this issue by cutting off the URLs after a specific number of variable strings ('?')

For example, let's look at three URLs:

http://www.about-seo.com/forums/thread.php?threadid=12345&sort=date
http://www.seo.com/forums/thread.php?threadid=67890&sort=date

All above three URLs point to the three different pages. But if the search engine purges the information after the first offending character, ('?'), now all of the pages look the same:

http://www.about-seo.com/forums/thread.php
http://www.seo.com/forums/thread.php

All urls point to different pages but now all pages looks the same . So static urls are most favourable . Static urls are indexed more quickly than dynamic urls.