Seems like the article is making a case for Yahoo buying Pinterest, not Tumblr. Correct me if I'm wrong but aren't Tumblr posts generally without context?
Correct. You want the right writers, though, and Tumblr has attracted an interesting set. You don't want too much garbage/noise on Tumblr, and so far (at least for me) this is the case. FB and Twitter have a lot of noise.
I respect Adam Rifkin's opinions a lot, partially because he's a great person and partially because he's the best-networked person in the world. http://tech.fortune.cnn.com/tag/adam-rifkin/
I may be wrong, but I feel like the second title qualifies him to maybe see things that others don't.