NoteFinder is an extensible PIM implemented in Python.
It was firstly developed as a simple command-line interface note-taking application that used a filesystem as database and featured tagging and search.
Now it has been rewritten to be as extensible and modular as possible.
Thanks to modular architecture it became possible to turn it into a full featured PIM able to store not only notes, but contacts, tasks, spreadsheets, bookmarks, web pages and any files too.
Unlike in most commonly used PIMs like MS Outlook, Kontact, Evolution, Mozilla Sunbird those provide different non-integrated interfaces to access different data, everything is tightly integrated and stored in a single database so you can use common interface to search for records, list, view and edit them.