Nice Question Bro...But you need to be more specific, as in which context you are asking your question. Website optimization could be Application optimization, optimization for search engines. Which could again be sub categorized.
tell me for all categories which you have specified
Gr88..you seems to be very much interested in the process. When you think or something clicks to your brain for your global presence, the formost thing comes to your mind is building a web portal. And therein the process starts. But building a webpage is not enough, you may hardly be recognized locally or to your trusted affiliates. But for global presence you should be visible on search engines. And to mark your presence on search engine your web portal should be optimized. So website optimization starts in development phase, continues in marketing phase rebounds to you in the form of maximum Return on Investment.
Thanks nitin... for your valuable information