ithought is a personal thought manager, allowing you to create and store entries that can be linked together via keywords. Through the use of various modules, it is possible to do a number of things with these entries, including uploading to a website as part of an online journal.

MindMapping displays knowledge in a tree structure so that the associations and links between knowledge "nodes" are visible. This implementation additionally allows one to archive the knowledge in graph form instead of a tree structure, to have multiple roots, and to add images, databases, and translations of whole books

ToutDoux is a project manager which lets you design a plan of action using a tree structure, with translations in French and English.

yank is yet another notekeeper for gnome.