It's funny you mention that, Frank, as that website is what lead me to a tag-based system.
I'm just not sure how useful it truly is given the way Evernote currently works.
In his example, he has the following in his tag structure (obviously, just a small chunk of it):
get published conf
So if I'm wanting to get the documents I've generated (or notes I've taken) for a particular conference, I have to either:
a) Know the specific conference
Tag it with the conference, but also the parent (and any parent up the chain that I may ever want to use as my "root" for a search)
c) Use other tags in conjunction and hope that they catch what I may want to search by in the future
As far as I can tell, there is no way to get all documents from my conferences.
I've seen the workarounds, but don't really like them, honestly. They tend to get more difficult to maintain with multiple levels which leads to a non-sustainable workflow and any tool is only as useful as your ability to stick to it.
Unfortunately, after my initial post here I ran across the hoards of other posts asking about this and they seem to generally be given an attitude of "everyone doesn't want this so you should just use something else" which kind of made me step back - mainly because I feel this could be done in a way that would allow those that want it to use it and those that don't to remain relatively unaffected (I honestly can't think of WHY you would have a nested tab that you DIDN'T want to show contents from children tags). Maybe it is due to the way my mind works as a developer, but when I see a child tag, I immediately think of it in an "...is a..." type of way - "launch conf is a conference", "a conference is a product/event/etc.", but this seems fundamentally different from how the Evernote team views them (which again, makes me wonder how people that DON'T want this put in place are using nested tags - a mutually exclusive parent/child relationship seems unusual to me, but I would really be interested - in all sincerity - in hearing from folks that do not want this addition).
But it seems unlikely that this will ever change, so I'll continue to try and find ways to lay things out that work around this limitation (Evernote may not call it a bug, so maybe they'll at least go for that term).