So it's only taken me a year, but I've sorted out the Tags function on the forum.
You'll see 'Hot Tags' displayed in the sidebar. The larger the tag or larger and bolder shows that the tag has been used on multiple posts.
Only the top 20 tags will ever show
You can click on the tag in the sidebar and you will be shown a list of posts with that tag.
Tags will work best if you use more granular terms, not "the black keys" or "photos" - the post should probably already be classified under the photos topic. A good use would be "moe.down" or "alfred mcmoore"
Of course, the search box will also allow you to search for a particular topic.
Obviously there are a large number of posts without tags. no probs, if you're in a post and don't see a tag, add one.
If you see stupid or offensive tags, let me know and I'll remove them