If you have change your permalink default (example : http://www.ajax-tutorial.net/?p=123) and change like this (example : http://www.ajax-tutorial.net/php-reference/php-case-functions-string/) to get familiar link for search angine like google. but you have found problem "404 error not found."
to fix this problem you must add you .htaccess and if you don't have .htaccess you must add in public folder where your blog location. this code .htaccess must add :
