Piggydb is a flexible and scalable knowledge building platform that supports a heuristic or bottom-up approach to discover new concepts or ideas based on your input. You can begin with using it as a flexible outliner, diary or notebook, and as your database grows, Piggydb helps you to shape or elaborate your own knowledge. Piggydb is a Web application provided as a self-contained package that contains a Web server and database engine.
The KiWi core system is a flexible platform for building different kinds of semantic social software applications on top (currently the Semantic Wiki and the TagIT application). It provides all the core services required in such applications, like editing and tagging, the storage of content and associated meta-data, its own triple store, transactions and versioning over content and meta-data, a linked open data server, and many small features semantic social software developers will like (like convenience services for working with ontologies or SKOS thesauruses, etc.).
IkeWiki is a new kind of Wiki (a so-called "Semantic Wiki") developed by Salzburg Research that allows users to collaboratively annotate pages and links between pages with semantic annotations. Such annotations are useful because they give machines a certain amount of "understanding" of the content that goes beyond merely displaying the page. This information can then, for example, be used for context-specific presentation of pages, advanced querying, consistency verification, or drawing conclusions.