At least in the trunk version. We can now tag almost all resources, like static Xhtml pages, pictures, links and of course blog entries. See the trunkdemo for some examples. We also made a new link plugin (and a link editor), which can be used as a little del.icio.us like replacement, but was mainly written for educational purposes. Meaning, people who'd like to write their own plugins for BxCMS should have a look at that. It's done as simple as possible, but nevertheless has some of the more advanced features of BxCMS. A real how-to will follow some day ,)
Our new metaindex stuff, on which the tags and related pages are based on, is soon finished. We will then have more new features like a site-wide search without relying on mnogosearch and automatic metadata extraction from eg. mp3s (id3 extraction) and jpegs (exif extraction) and a super-duper new livesearch, which will use this metaindex. Silvan is also currently working on a metadata plugin with the goal to automatically build podcasts from uploaded mp3s.
And by the way, ecto has a cool new Tags feature, which you can already use to set the tags of your blog entries. See the docs for details (at the bottom of that page).