Tags in Bulletin Boards

I was just pointed to three bulletin board systems that either have adopted the concept of tags, or are fully based on it. A couple of weeks ago I posted about this idea. Apparently I wasn't the only one thinking about it at that time. The three boards are: * bbPress, written by the same guy that wrote WordPress. Tags are included here next to the usual boards, so it hasn't replaced them. Still it looks good, you can find an example of what this looks like at the WordPress support forum. * Tagifieds is practically exactly what I had imagined the new kind of forum to look like. There are no boards or categories, just one big namespace containing all topics. Tags are listed at the right and if you click them you will see the topics that are tagged with that tag, it will also show related tags. Quite nice, although in a way it doesn't feel quite right yet. I don't know why. * Tagsurf looks a lot like Tagifieds. In its current form I don't think it's very usable yet, unless your entry is the Rcent Posts page. But I'm sure it well get there.