I really like the idea of tags, but have largely abandoned tags since Evernote 5 took away the ability to see what “active” tags there are for a particular notebook or search in the sidebar.
I used to have high level categories with tags that began with the symbol “/”, and then when I clicked on one of those tags the list of tags in the side bar would only show the remaining tags for results in that search… this really let you organize your notes in one big notebook and drill down to what you were looking for or see what was in the search results.
However, I have been unable to figure out how to get this back in Evernote 5, other than clicking on the tag icon to get the list of available tags to appear…. this was a really bad “improvement” they made in 5, which has basically caused me to increase my notebooks from a handful to close to 100.
I now equate each notebook with a manilla folder in my old hard copy filing system… when a “file” is closed or no longer active, I either merge all the notes or tag them all with the same thing and move them to an archive notebook.
This works for now, but I will likely switch back if Evernote reintroduces the remaining tags in the sidebar.