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They are just stale categories d we should have more interesting categories maybe show some links to some popular new future Communities? Like Earth Porn, GirlsGoneWild TwoXChromosome, Videos etc etc those will be HUGE on steemit when we have communities (substeemits )

You should soon be able to favourite categories and NSFW will probably be possible to enable in settings along with more diversified NSFW categories.

Diversity // Quality // Pertinence

One of the main goal is to provide a better diversity in the ecosystem but default categories are the trending ones.

I think playing with the timeframe (shortning it) would make different tags come up.

Then you could have a rising tag list, which would be the delta of last week # of posts or $ in a tag.
Lots of things are possible the steemit default has been abused and is now almost static and meaningless.