Who's going to write it? How about the writers for The Atlantic, The Nation, The New Republic, The Wilson Quarterly, The Economist, The Paris Review, etc. I could fill up the length of a long-form article with names of publications that have long-form writing.

The real question is, who's going to pay for it? This is like when someone complains that there aren't any good programmers out there, and, P.S., they're paying $25k a year. The article talks about 2000-3000 word articles. At the rate Tumblr's paying, that's $80-$120 per article. Who are they kidding? At those rates, if you're an established writer, you're better off posting to a personal blog and relying on ad revenue.

There have been a few magazines (both online and print) that have recently managed to establish themselves as reputable publications that have good writing. What they've done is pay above-market rates to attract good writers. After all, why would you publish in some no name publication instead of The Atlantic? Tumblr seems to be using the opposite strategy.