Multi user application

[eluser]Tripic[/eluser]
As far as how it will impact the servr it should really be noticable but the first thing you should do is figure out exactley what you need in the application then break it down by what you want to do first im working on one right now and i went with a user auth system to start so that i can start building the site security in from the start rather then adding it later. I know this isnt much help but without any ideah of what your working on theres really not much i can say