The Apache Traffic Server (TS or ATS) is a modular, high-performance reverse proxy server, generally comparable to Squid. It was created by Inktomi, and distributed as a commercial product called the Inktomi Traffic Server, before Inktomi was acquired by Yahoo!. Traffic Server has been actively used inside of Yahoo for over 4 years, serving billions of requests every day. As of fall 2009, Traffic Server is an Open Source project, and in April 2010 the Apache Traffic Server was promoted to a top-level project of the ASF.
Xapian is a search engine library, scalable to collections containing hundreds of millions of documents. It's written in C++ with bindings for Perl, Python, PHP, Java, Tcl, C#, Ruby, and Lua. It is a highly adaptable toolkit that allows developers to easily add advanced indexing and search facilities to their own applications. It supports the Probabilistic Information Retrieval model and also a rich set of boolean query operators. Omega is a Web search application built upon the Xapian library. It can index a Web server's document tree (including HTML, PDF, OpenOffice, MS Word/Excel/Powerpoint/Works, WordPerfect, RTF, PS, etc.), or data exported from arbitrary sources (e.g. SQL databases).