Everything is Miscellaneous
There is a very nice talk on Google Tech Tacks named Everything is Miscellaneous where the speaker discusses problems with data organization/categorization. I am not going to cover anything from the speech here since it is better to see it. Myself I found it very relevant to a lot of problems people face everywhere like, for instance, categorizing/tagging blog posts, bookmarks, files/directories in on a file system or mailbox folders. Watch it :)