I’m not sure these instructions are correct. Investigating further…

The correct RegEdit node appears to be

HKEY_CURRENT_USER \ Software \ Microsoft \ Windows Live \ Writer \ Weblogs \ {GUID} \ UserOptionOverrides

The next question is, does it actually work? It appears to. At least, it adds the Tags box to the UI:


Update: Well, it looks like it would work, but it doesn’t seem to persist. The tag box is no longer visible in my instance of LiveWriter.