Hi all by dint of view this forum, I see that there are many things not to do if you want to be well referenced. It will serve many people I think So I begin with what I think I have understood, that is to say not much, lol. * No Frames * No PHPSESSID * Not too variable * No id and ID * No Flash * No Javascript For frames, there are special tags. For PHPSESSID we can pass the session id using cookies. For variables, we must make the url re-writing. For id and ID, just rename them. I probably forgot tons of things to you!