When I subscribe to a new StackExchange site, I usually go to the Tags page and look for existing (and possibly popular) tags to add as favorite, but also to look for subjects that I'll probably ignore systematically.
However, while it is easy to add a tag as favorite by starring it, the only way I know to add a tag as ignored is typing its name in the Ignored Tags section of the site's homepage. If I'm lucky, I soon get an autocompletion while typing, but IMO even so that's a waste of time.
Old question: wouldn't it be better to have an "ignore tag" or "add as ignored" link somewhere in the tag mouseover and/or in the Tagged Questions page?
EDIT: I just learned about the new tri-state star from the Recent feature changes page. I am happy about that since it solves my problem (I was tempted to answer this question with that), but now I wonder if this solution is clear enough for new users. In fact, even if the feature is explained with popup text over the star, I probably wouldn't have noticed if it weren't for the Recent changes post. I'm not asking this as a proper new question, since it is very similar to the original one anyway.
"New" question: Should the tri-state star in the tag mouseover be better advertised, and/or should we have other ways to ignore tags, like a link in the Tagged Questions page?