First thing is first in developing a functionality website called CMS ( Content Management System ). Large functionality website takes time to grow and develop both the front end and back-end. Front End is the physical colorful & theme design you see in your website. Back End is all the functionality scripts and customization to all the user rights and authorized access.
Core value of the web-designer are good in colors and themes while web-developer are more interested in back-end script customization. The key is to work in harmony both the web-designer and web-developer to get the best suited in your master plan of your blue print website.
A website blue print is a powerful tools to see vision and mission of the whole architecture in long term webdevelopment.