MyTetra is a full-featured, open-source, cross-platform note manager
(PIM-manager) used to collect and accumulate various kinds of information.
All entries (notes, articles) are organized in a tree structure, as well
as supplied with keywords tags that allow you to quickly find the right
entries.  Links between records, attachments, encryption, detailed search,
synchronization, copying from the browser, one of the best visual WYSIWYG
text editors -- all this is in the PIM-manager MyTetra.  It is powerful
program for data memorization and structuring notes.