Also note that requests and responses are bits on the wire. Do not assume you can trust client data. Do not put client data directly into SQL or back on the p

Also note that requests and responses are bits on the wire. Do not assume you can trust client data. Do not put client data directly into SQL or back on the page. This includes headers. Nearly all aspects of a request can be forged. Security info: http://www.slideshare.net/simon/when-ajax-attacks-web-application-security-fundamentals-presentation http://www.slideshare.net/simon/when-ajax-attacks-web-applic... After you get security and basic dev down, you can start to worry about scaling. It's important, but it's a nice problem to have. Deal with it later.