I know the big picture but can't put it in place

Question

I'm interested in web development and by that I mean the bigger projects like facebook or twitter. I know the basics of java, css, php and mysql. I know there is a lot more out there. I read about it. But I don't know what the purpose is and how to put in place.

Things like: Scribe, thrift, casandra, Unix/Linux, shell/perl/python scripting, PostgreSQL, MongoDB, non-relational NoSQL datastores, JVM, nginx

I want to know why they need it, how they use it and what te purpose is.

What I need is a book like technical background of facebook for dummies or so. Are there any books or websites that explain this from scratch?

Thank you!

EDIT:

Thank you for your answers! You have been very helpful. I was in the assumption, experienced programmers know almost anything about the technology there's used today. But as I read, you can only know so much and I need to figure out which technology to use. I take on the encouragement to start building small. And will take on php and improve my skills from there.

Thanks again!

Answer 1

http://highscalability.com/

This is one of the best sites out there. There are several case studies describing what and why many websites use, and pointers to further references. I would also look at the Google Scalability Conference 2007 talks

http://www.google.com/search?q=Google+Scalability&hl=en&client=firefox-a&hs=YUg&rls=org.mozilla:en-US:official&prmd=v&source=univ&tbs=vid:1&tbo=u&ei=fl4OTPUkorIwueCQxQw&sa=X&oi=video_result_group&ct=title&resnum=4&ved=0CDIQqwQwAw

Answer 2

It's all about choosing the right tool for the job in my eyes. There is so much technology out there it's impossible to learn it all. Just choose the subset that will work for you.