Mavericks has a great feature that allows you to tag files, essentially giving them keywords that you can use to easily search for files later on. You could organise your files into folders which you may have done but files that have the same tags may not necessarily belong in the same folder. For example, lets say you have folders for your holidays like London, Sydney or Orlando. That would be well organised, now what if you were interested in architecture or food and you had pictures in each of those folders, well you could copy them to another folder dedicated to those, but that takes up more space and could be more time consuming. What the video below and you will see how useful tags are. This does not mean you should stop putting them into appropriate folders.