hr1(I just mentioned this in a resolved topic, before realising that was not a good place for it!)
I have just installed WP 2.7 this morning - clean install, NOT an update of any kind. Still using the default theme. Tags are not displaying anywhere.
I can add tags to a new post, they get saved somewhere and I can view and change them when I edit the post, but they aren't displaying anywhere on the blog. I added the tag cloud widget and they displayed there, but there's nothing showing on individual posts (or anywhere else that I can see).
