Mm. Just because you can see a pattern doesn't mean it's not actually random. ;)

Though if you're not voting on anything, there's a chance you're seeing the same set of poems over and over again. Because it's not actually entirely random (I think that's on the About page) -- it's showing you a random poem weighted by how long it's been since it's been voted on.

And maybe someone just voted on a lot of Cadacus stuff all at one go, so they're in a pool together.