I started collecting notes on various interesting energy technologies and scientists like Nikola Tesla and Viktor Schauberger into a mediawiki installation. Mediawiki didn't impress me too much, things got very unorganized, so I transferred everything into Drupal (manually, not much data).
Current highlights on MERLib:
Free tagging:
Free tagging allows one to embed keywords into nodes which allows one to more easily store and find the content. I've divided the tags up into: tags, years places and persons.
Examples:
http://merlib.org/node/811
http://merlib.org/tags/
Here is a list of articles tagged with both "sweden" and "water": http://merlib.org/taxonomy/term/285,11?
One still has to use the taxonomy browser, http://merlib.org/taxonomy/term/285,11?, to put together these combinations of tags, unlike on http://del.icio.us. Maybe we can put that feature on the wishlist?
Pathauto
Currently the Pathauto module generates paths to the tags (tag/airplane, year/1924).... Works well if one knows what one does. Earlier I let it generate paths for everything, but it was a bit complicated and felt a bit too massive. KISS (Keep it simple stupid)
Google map
Some articles have been given geographical cordinates and show up here: http://merlib.org/gmap/