Yahoo will Tumble. 1.1 billion dollars for 13million in sales. Didn't Yahoo learn that eyeballs don't translate into money. Yahoo is just a Madison Avenue company trying to sell ads. Anyone can do that on their blog. Buying blogs is like buying someones home mail address. You don't own the house though.
The difference is the PnL.
If they invest a billion in R&D and 18 months to develop a successful site like Tumblr is today, it will require that the Profit and Loss statement be negative for 6 quarters and still nothing assures them that it will be successful. Do you think Wall Street likes that?
On the other hand an acquisition goes outside the PnL and the Business looks positive. That is why she is buying, the buys are an R&D outside the PnL so you do not take a wammy for doing it. Technology Business is tricky and MM knows the rules well. She is developing lighting speed, Flickr was a forgotten asset, not anymore, something is coming.