Just ran across this bit in some CMS documentation:
For example: You have an article about iPhone and topics Apple and Smartphones, respectively. Topic “APPLE” may contain tags: MacBook, iPod, iPhone, OSX, and topic “SMARTPHONES” tags: Blackberry, iPhone, Nokia, Motorola, Palm. By tagging the article with Apple::iPhone and Smartphones::iPhone you will ensure that article appears on both topics in navigation and provide cross-category posting.
By my thinking, this makes tags hierarchal and thus completely misses the point.
When setting the tags for an article, you should be thinking about the content (“hey this is about iPhones!”) not the multiple destinations the article will -or should- land in.
You’ve just posted your 40th article about iPhones, and tag it “Apple::iPhone” but forget to tag it “Smartphones::iPhone” does that mean the article is about Apple iPhones that are no longer Smartphones?
By advising your users to create *two* iphone tags means you’ve implemented tagging wrong.