Part of the Case Study Series
As before, this is a series of my own top-rated questions; I'll give my own opinions about whether or not they are on-topic, and anyone else can give their own opinions. I encourage everyone to provide their own answer, even if they agree with the ones already posted.
How many nanobots can I have in my blood?
About Worldbuilding? I would say that this is about worldbuilding. I wanted to know about a near-futuristic technology so I could use it in a sci-fi world where its applications could have large and far-reaching effects.
Risking Off-topic? I don't know about this one, I think it's on-topic but maybe I could have asked it on Biology SE.
How could I scientifically explain ice breath?
About Worldbuilding? Again, I think this one is on-topic. It's about how dragons would work.
Risking Off-topic? I can see this as being idea-generation, but for some reason it doesn't seem too idea-generation. I think my intention was for answers to draw upon real-world evolution and choose the solution that was... the most plausible (I think I get it now, Tim B). This goes along with what some people have been saying, that idea-generation may not actually be a bad thing as long as its scope is thin enough.
About Worldbuilding? How to tell time in an interstellar society definitely seems about worldbuilding to me.
Risking Off-topic? Again, this could be idea generation, and I think it's an even bigger culprit than the last one. I don't think I have a defense for this one.
Can you shoot someone with a bullet... from orbit?
About Worldbuilding? It has applications in military strategy, and the military is pretty important for changing worlds, so yeah, I'd say it's about worldbuilding.
Risking Off-topic? Well, this one was closed as not about worldbuilding, so maybe I have a skewed perspective. But I think orbital ballistics is way more on-topic than some of the other stuff we've had recently, so please, if I'm wrong, explain how.
That's no Moon: Planet-sized Plants Possible?
About Worldbuilding? I'm building a world out of plants. I think it's definitely about worldbuilding.
Risking Off-topic? Nah, I think this is cut-and-dry on-topic. 'Can it be done' is way narrower than 'how can it be done' or 'why would it be done'.