Greg Sargent's top 10 neighbors are almost entirely fellow journalists — nine of the ten share his subcategory, with Lawfare (0.99, a blog) the lone exception. Similarity here measures how closely two entities' audiences resemble each other in composition; scores this high and this uniform signal a tightly defined audience cluster.
The shape is flat: scores run from 0.99 down to 0.99 across the top four — Susan Hennessey at 0.99, Sam Stein at 0.99, Josh Marshall at 0.99, David Fahrenthold at 0.99 — and compress only slightly by position 10, where Ashley Parker sits at 0.99. No single neighbor pulls away from the pack; the band spans roughly 0.986 to 0.992. The cluster is defined almost entirely by political and national-security journalists: Maggie Haberman (0.99), Josh Dawsey (0.99), Chris Cillizza (0.99), and Jonathan Swan (0.99) round out the set alongside Lawfare. The one non-journalist in the top 10 is itself a publication with a national-security and legal focus, consistent with the rest of the cluster's character.
What the shape reveals is an audience with very little diffusion — it overlaps heavily with a specific stratum of political journalism and barely strays from it within the top 10.