[grzm]

I suspect it's simply a function of which one happened to catch people's eye and where they started their discussion. Multiple submissions on the same topic (from the same or different sources) aren't that uncommon. Once one gets some momentum, it's likely to be reinforced: it'll appear higher on the front page, more people will notice it, more people will comment, more people will notice the comments on that article, which will make them notice that article, et cetera. I don't think you can read much more into it than that. I wouldn't be surprised if a mod comes along and merges the comments from one into the other, if they notice it.

What would be interesting is if they had exactly the same upvotes and comments.