Yioop - Open Source Search Engine Software

Yioop is an open source, PHP search engine capable of crawling, index, and providing search results for hundred of millions of pages on relatively low end hardware. It can index a variety of text formats HTML, RSS, PDF, RTF, DOC and images GIF, JPEG, PNG, etc. It can import data from ARC, WARC, Media-Wiki, Open Directory RDF. It is easily localized to many languages. It has built-in support for new feeds, discussion groups, blogs, and wikis. It also supports mixing indexes to create mash ups.