How do sites quickly make updates to thousands of pages with user created content without affecting the old content. I know you can do it in php resulting in urls such as .../profile.php?id=000000000&ref=nf such as facebook does. I don't know php but maybe there is a way to get the same effect without affecting the url (witch is my goal). Digg.com is another site that i saw go through an update, updating all old pages as well and there urls don't look like that. At first I thought it was all done through css but I don't think some of that changes they made are possible through pure css. If you can help me in any way learning how to build this capability that would be great. thanks