What front-end and back-end technologies do Google and Facebook use?

http://web.archive.org/web/20110708015633/http://panela.blog-city.com/python_at_google_greg_stein__sdforum.htm

• Where is Python used?

  • The Google build system is written in python. All of Google's corporate code is checked into a repository and the dependency and building of this code is managed by python. Greg mentioned that to create code.google.com took about 100 lines of python code. But since it has so many dependencies, the build system generated a 3 megabyte makefile for it!
  • Packaging. Google has an internal packaging format like RPM. These packages are created using python.
  • Binary Data Pusher. This is the area where Alex Martelli is working, on optimizing pushing bits between thousands of servers
  • Production servers. All monitoring, restarting and data collection functionality is done with python
  • Reporting. Logs are analyzed and reports are generated using Python.
  • A few services including code.google.com and google groups. Most other front ends are in C++ (google.com) and Java (gmail). All web services are built on top of a highly optimizing http server wrapped with SWIG.

I can tell you that Facebook uses PHP as a frontend presentation layer and backend is mostly MySQL and (for message search) Cassandra. More information can be found here.

Google uses BigTable for backend repository (I don't know if they use MySQL or other technologies).