Retaining user interactions forever...!?

i know i posted something like this, but i want to rephrase part,

i want a swf. and post it on the web, that

  1. a user clicks and adds a “circle” or whatever shape, thats a movie clip to the stage or “screen”.

  2. and when they or anyone else comes to that site they can see all the previouslly added movie clips, and can add there own, ( they cant move or change the previouslly added ones, but they can add there own and put it where they want. )

i know how to allow people to add things, but everytime you go back to teh site its refreshed, so basically i want a site that retains what people have done each time its launched.