DotNetWikiBot Framework is a full-featured client API with a console interface that allows you to build programs and Web robots easily to manage information on MediaWiki-powered sites. DotNetWikiBot Framework is intended to help with many complicated and routine tasks of wiki site development and maintenance. Any .NET language can be used to access DotNetWikiBot library functions. Only minimal programming skills are required to make bots with DotNetWikiBot Framework.
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).
focuseek searchbox is a family of easily installable full-text search engines that can spider Internet and intranet data sources (Web sites, newsgroups, FTP sites, and others) or index data you feed to it and make it available for searching. It supports a variety of input formats (among them HTML, PDF, Microsoft Word DOC, and RTF), and is easily scriptable via SOAP and extendable through plugins. It can scale to millions of documents and comes with a full-fledged GUI client, a built in Web search portal, and an RSS server.
libcurl.mono is an object-oriented binding for the libcurl Internet client API. It supports rapid-development of powerful Internet clients in C# that can run within the mono runtime. With libcurl.mono, for example, you can develop FTP and HTTP clients without having to code down at the socket level. There are a number of sample applications to get you started.
mojoPortal is a cross-platform object oriented Web site framework. It supports PostgreSQL, MySQL, Firebird, SQLite and MS SQL for the backend. It includes a content management system, forums, blogs, photo galleries, newsletter, polls, surveys, an event calendar, an RSS feed aggregator, and a skinnable design.