But, as a total replacement to the forum system it is hard to navigate and hard to find related topics when you do not know what might be related. or what might exist already.
Our site search dropdown offers an autocomplete feature to help you find tags. When you are in a forum/forum thread, it presents a list of the most popular related tags. When you're on the homepage/elsewhere, it presents a list of the most popular tags across the site as a whole. As you type, the list filters itself, but it always stays aware of what section you're in. So, for example, typing the letter 'c' while in the software development section will present you with C++ and C#, but typing the letter 'c' while in the web development section will present you with CSS.
All that was easily available on the old C++ forum. Now, the tutorials, recommended books, etc discussion topics are no longer part of the C++ tag
Those are the sticky threads, which are currently being retooled to be presented in a different way. That's not related to the tagging system. It's just something else we're in the midst of upgrading on the site right now for reasons of a lot of them being very outdated and no longer entirely relevant. If, and when, they're brought back, they'd be attached to the C++ tag the same way they were to the C++ forum.
Maybe the sticky posts have, or could have a tag of their own.
It's definitely an idea worth thinking about to have tags that can only be used by moderators. We wouldn't simply be able to tag the stickies with a sticky tag within the existing system, because then every single person who thinks they have an important question and want it to get seen by more people will do the same.
One thing I do not find particularly fantastic about tagging system, is after navigating to particular section, having to scroll to the bottom to click on a tag I'm looking for.
The reason the tag cloud is at the bottom of the page is because it's simply secondary navigation, similar to related articles, of the most popular tags used within the forum. It's not meant to serve as the primary means of navigation.
That being said, the problem is that there are effectively an unlimited number of tags, and a growing number of popular tags, and so having a comprehensive list at the top of a forum would not make much sense. You'd be scrolling endlessly. That's why the main site search was retooled to, first and foremost, be an easy way to find tags. It has an autocomplete dropdown that is conscious of the section of the site you're currently in to present you with an easy way to discover all tags.