http://lucene.apache.org/solr/ <- CNet use this

solr if you want to build a search engine, ok la search your own web page

http://hadoop.apache.org/ <- Yahoo use this, facebook too

a map reduce framework, if you want to play google.
It run the whole thing in batch thoug

http://djangoproject.com/ <- NY Time use this

for python based web framework

http://rubyonrails.org/ <- 37signals use this

just because you have python, and decide to use ruby

http://clojure.org/

a lisp to talk to java

then the whole set of NoSQL database
MongoDb

Couchdb

Cassandra <- facebook use this

This post has been edited by sweemeng: Mar 16 2010, 11:10 PM