#128 Tagging system and tag cloud display

[Kilian]

I'd love to see a tagging system similar to what you can on flickr resp.
del.icio.us, where you can add tags to any item in the CMS on the fly
describing its function, content etc.

I would also be nice to have a "tag cloud" display which tags are used
most often on the site by showing a list of tags, which depending on how
often they are used will show in larger font sizes.