Is This Irony or Just Odd?

An article in Monday's Washington Post about "homophily" -- "a somewhat grand word to describe the idea that birds of a feather flock together" -- entitled "Why Everyone You Know Thinks the Same as You" reminded me of the old joke about the Harvard professor who, in 1972, couldn't understand how Richard Nixon won re-election by a landslide because everybody he knew had voted for McGovern. ("Don't Blame Me: I'm from Massachusetts," said the famous bumpersticker.)

The article, by Shankar Vedantam, includes this tidbit (note the last sentence below):

Ever larger numbers of people seem to be sealing themselves off in worlds where everyone thinks the way they do. No Walter Cronkite figure unites audiences today, the sociologist noted. We can now choose cable stations, magazines and blogs that see the world exactly as we do. If the research on homophily is right, those heavily e-mailed partisan screeds from the op-ed pages are largely talking to those who agree with those points of view to begin with.

What's odd -- or ironic, I don't know which -- is that, according to the Post's calculations, Vedantam's page A2 article is number two on the list of the 20 most emailed article from the Post's web site.