web application like Facebook or LinkedI

The answer :

I found some web Application .net :

http://cks.codeplex.com/

http://www.dnnsoftware.com/platform

http://friendev.codeplex.com/

http://chatme.codeplex.com/

Sure, who knows better, please, you can share.

For the php Web application :

https://www.getanahita.com/html/get-started

https://mahara.org/

http://www.phpfox.com/#intro

Have a great day.