Alkaline is a full-featured standalone search and index server. The spider is a fully remote indexing daemon which includes support for all standards like robots.txt and "skip" meta tags, and allows multiple distinct configurations and search groups (searching many different sites from your server), including complex regexp indexing paths, authentification, filters for various document formats, XML-based online management and statistics, mrtg-compatible perf numbers, and more.
ASPseek is an Internet search engine, written in C++ using the STL library. It consists of an indexing robot, a search daemon, and a search frontend (CGI or Apache module). It can index as many as a few million URLs and search for words and phrases, use wildcards, and do a Boolean search. Search results can be limited to time period given, site, or Web space (set of sites) and sorted by relevance (PageRanks are used) or date. It is optimized for multiple sites (threaded index, async DNS lookups, grouping results by site, and Web spaces), but can be used for searching one site as well. It can work with multiple languages/encodings at once (including multi-byte encodings such as Chinese) due to optional Unicode storage mode. Other features include stopwords and ispell support, a charset and language guesser, HTML templates for search results, excerpts, and query words highlighting.
cthumb allows you to create Web albums of digital pictures with thumbnails, captions, and several different views of the collection, including (optionally) several languages and resolutions. An album is composed of a series of pages, each composed of a collection of pictures. You can have several annotations per picture, and can customize almost everything in the way the albums look on the screen.
DirList is a user directory system that runs as a CGI to serve up user lists, search for various user attributes, view their web sites, define personalised user attributes, and keep it all synchronized automatically with the underlying operating system's user database on periodic intervals with cron.
Enzyme is an architecture for creating user-searching-user applications. Right now, it is primarily useful as a resume create/search and HR management system. However, it's potential uses are wide-ranging, and it offers PHP developers an alternative to relying on simple "keyword" searching systems.
FemFind is a crawler and search engine for SMB shares (provided by Samba/Unix or Windows) and FTP servers. The crawler maps the filesystem structure of your shares to a MySQL database. Then, the Web interface or a Windows client can be used to quickly locate any file on the network.
Greenstone is a complete digital library creation, management, and distribution package for Unix, Windows, and Mac OS X. Users create collections by gathering a set of input documents, specifying a configuration file, and running the build script. It provides full-text and fielded searching, browsable indexes, customised formatting, metadata extraction (acronyms, languages, etc), a Z39.50 client, and many other features. It supports many input formats, the interface is configurable and multi-lingual, and collections can be distributed on the Web or on CD-ROM.
ht://Check is a link checker derived from ht://Dig. It can retrieve information through HTTP/1.1 and store it in a MySQL database so that after a "crawl", ht://Check can return broken links, anchors not found, content-types, and HTTP status codes summaries. ht://Check also performs accessibility checks in accordance with the principles of the University of Toronto's Open Accessibility Checks (OAC) project, allowing users to discover site-wide barriers like images without proper alternatives, missing titles, etc. A PHP interface lets the user query and view the results directly via the Web.
The ht://Dig system is a complete WWW indexing and searching system for a domain or intranet. This system is not meant to replace the need for internet-wide search systems like Lycos, Infoseek, Google, and AltaVista. Instead, it is meant to cover the search needs for a single company, campus, or even a particular sub-section of a Web site.