DataparkSearch Engine is an open source search engine written in C. It is distributed under the GNU General Public License and designed to organize search within a website, group of websites, intranet or local system
Egothor is an open source search engine implementation written entirely in Java to ensure cross platform compatibility. Egothor is able to recognize many common file formats: HTML, PDF, PS, DOC and XLS. Its architecture means that other file formats can be easily added. The engine can index about 50 pages a second and comes with a high capacity crawler robot which is compatible with the robots.txt standard.
Terrier is a software for the rapid development of Web, intranet and desktop search engines. More generally, it is a modular platform for the rapid development of large-scale Information Retrieval applications, providing indexing and retrieval functionalities.
Puggle is an open-source graphical desktop search engine written exclusively in Java. It provides full text and metadata search over files, folders, music, photos, web pages and more that are stored locally on your computer.
Wikia is a selective free web hosting service for wikis (or wiki farm) operated by Wikia, Inc., a for-profit Delaware company founded in late 2004 by Jimmy Wales and Angela Beesley. Wikia particularly targets communities, both those established offline and those with a purely online following. Wikia is free of charge for readers and editors and licenses user-provided content under the GNU Free Documentation License or, in the case of Memory Alpha and Uncyclopedia, a Creative Commons license.