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Obviously we get a lot of these here already. But I'd be looking at something with a wider reach and encompassing more fields. Or separate communities for each field, as otherwise there'd be a skew in the favor of the biggest communities (as we get here for some languages for instance... but I digress).
I know HN is not always necessarily about "latest" or "current" content either, but you get the idea.
(Tricks to extract most popular articles from HN, Google Scholar or others are also welcome, of course ;))
Update: title fix, didn't know the etiquette.