When deploying a web application for production you'll most likely be pre-compiling it for security and speed but be aware of one misleading feature of pre-compiling: the web.config.
Although the web.config is left in place and can be edited not all the changes you put into it will work after deployment. During pre-compilation some of the settings in the web.config are compiled into the binaries (such as the Profiles sections), so even though you are changing the section in the web.config it will not show up in your application.
The way to get around this is to choose to make the site 'updateable' when publishing. This option is not there for Web Application projects so you have to use the Web Deployment Project Add-in from Microsoft.