I don't know what Paul Krugman is doing on that computer, but it's not tweeting. (Scott Eells/Bloomberg)

The Krug explains why he stays off Twitter:

One reason is that I have better things to do with my time. Another is that I don’t think my instant reactions to things are especially interesting. But I have to admit that I’ve also been aware for some time how many people end up destroying themselves by tweeting something really offensive.

Why do people do this? Well, it turns out that many prominent people have inner demons of one kind or another — often homophobia, but also racism, sexism, or just some kind of generalized contempt for large numbers of other people. And social media make it all too easy for those demons to slip out in front of a large audience.

I don’t think I have any demons like that, but who knows? And if I do make uncomfortable discoveries about myself, I’d like to do it in private, thank you.

Good points! But this actually explains too much. After all, Paul Krugman is on Twitter! He's got an automated account under the handle @NYTimesKrugman.

You might say that that's cheating: The account simply autoposts links to the economist's columns and blog posts. Well, sure, but that's one of the truly essential functions of Twitter: As more and more people curate their daily reading on this social network, it's really helpful for people who like Paul Krugman to be able to keep up with his newest work by checking in with his Twitter account.

The proof is in the tweeps: @NYTimesKrugman has more than 1 million followers.

This tracks with my experience, too. A few years back I began worrying that I was sending too many Wonkblog posts out through Twitter. Maybe my followers were getting annoyed. So I asked. And the response, overwhelmingly, was that people wanted more posts sent through the feed -- that they weren't following me to keep up with my 140-character thoughts so much as to keep up with posts on Wonkblog. The idea that people were coming for my brilliant, pithy tweets was just my ego talking.

Nowadays my Twitter feed is a hybrid: There's a modified autotweet for Wonkblog posts (modified in the sense that I can schedule and edit the tweets before they go out, if I want), and I do a fair amount of tweeting on my own. I do the personal tweeting because I enjoy it. But I'm pretty sure it's the links that add the most value.

Which is all to say that Krugman isn't rejecting Twitter. He's just using it extremely efficiently.