That's definitely an interesting thought. To reduce the amount of deliberate crawling of the search space (where a person has to check the surrounding tags of individual tags) what would you think of a Discovery page?

What I'm imagining is that there's a page that you go to and it shows you the normal posts filtered by your subscribed tags. Unlike other pages though, there's a slider that goes from 0 to `n`.  The slider position represents the number of hops from each tag, and as you ramp it up the specificity of your filters loosens and the results get fuzzier. That way you can find "novel" posts outside your comfort zone, without going all the way to the unfiltered stream.

Of course, all these features assume an amount of activity that warrants them. The Discovery page doesn't make much sense if all tags are effectively 1 node away and therefore equivalent to the unfiltered stream, haha.