One weakness with many blog engines, Subtext included, is that it is difficult to change the tags and categories for multiple entries at a time. In general, most blog engines streamline the workflow for tagging and categorizing a single blog post.
Fortunately, Marco De Sanctis, a friend of Simo (a core Subtext Developer) wrote a nice application that you can use to bulk categorize and tag multiple posts. He developed it using Subtext as a test-bed so it handles the fact that we use the rel-tag microformat within the content as our tagging mechanism. Sweeeeet!
Many thanks to Simo for blogging about this and to Marco for writing this.