Morcego is a 3D graph browser for viewing and navigating any graph-like structure. Examples of such structures include social networks, site maps, hierarchies, and genealogy trees. It currently only support simple graphs. It's already integrated into TikiWiki. Morcego is not meant to provide a solution for the end user, but to be embedded in a Web application by developers. It's a Java applet that communicates with an XML-RPC server to load the graph that is displayed.
silk web is a Web-based hypertext tool with an emphasis on linking. Creating links between nodes in silk requires just one mouse click -- you never need to manually type node identifiers (e.g. URLs or CamelCase node titles). It can also track links to the external Web, and you can manage these links with the same one-click functionality. It works well for organizing ideas and the connections between them (it was designed for personal note-taking), though it can also function as a public space for collaboration, much like a Wiki (like a Wiki with smooth linking).
JSpell is a server-based spell checker that allows you to spell check any HTML input field and form. It is i18n compliant and has dialogs for multiple languages available. It can be used to add spell checking capabilities to HTML forms on your Web site. This spell checker is compatible with JSP, ASP, CGI, PHP, Cold Fusion, Oracle Forms, etc.