You can read about it and all the predictions, cheers, jeers and whatever just about anywhere in the Internet industry press mainly because there is not much else going on.
In looking at the various reports that have tried to make sense of the purchase there is no more interesting than Yahoo’s own post on Tumblr which says,
I’m delighted to announce that we’ve reached an agreement to acquire Tumblr!
We promise not to screw it up. Tumblr is incredibly special and has a great thing going. We will operate Tumblr independently. David Karp will remain CEO. The product roadmap, their team, their wit and irreverence will all remain the same as will their mission to empower creators to make their best work and get it in front of the audience they deserve. Yahoo! will help Tumblr get even better, faster.