In episode 86 of Semantic Mastery's Hump Day Hangouts, one viewer asked about converting existing WordPress sites with less than 100 posts into a virtual silo.
The exact question was:
I recently saw your video on Silos. I have an existing WordPress site with a little more than 100 posts that I've been thinking about converting to silo. Is it worth converting to a url/directory silo or is a virtual silo enough??