Open threads are posts with little to no initial content, because the intention is for readers to use the comments area to discuss a topic amongst themselves. They're more commonly associated with online forums, but can be used on blogs if the readership "community" is active enough to sustain them...Which means it's up to you now. Are there enough committed readers to make this idea fly? If any of the open threads prove unpopular, they'll come to a swift end. It's as simple as that. I don't want DMD to fill up with too many sparse posts containing no comments*, but I'd love to see active in-house discussion about TV shows sans a review to kick things off. Suggestions for open threads are welcome, too. I've heard QI, Skins and Supernatural mentioned.
At this point, I'm unsure if I should "open thread" for TV shows I don't watch (or at least have a mild interest in), because I'm worried the blog may feel "hijacked". It exists to reviews/comment on media I, personally, watch and enjoy, and I don't want to feel like a stranger in my own blog. So, we'll play that by ear...
Also; don't worry, the majority of content will always be reviews from yours truly, so these open threads won't become too ubiquitous, even if they prove very popular.
* I had enough of that reviewing Paradox.