It looks like a lust-to-dust content strategy.  They capture as much high quality and highly viral content at the front end of the funnel, automatically curate it through a variety of means, repackage it for portals and email and mobile.

If i had to summarize their strategy, it would be great content = great users = great revenue.

"Lust-to-Dust" - brilliant!

The themes are mobile and personalization:

http://pandawhale.com/post/14607/yahoo-acquisitions-2013

How it all fits together remains to be seen.

But at the very least it makes Yahoo seem relevant and working on cutting-edge stuff.

And it makes Yahoo seem like the kind of place good people would want to work.

Both of those help with recruiting, I believe.

One challenge: founders only stay in companies that acquire them for as short a time as possible:

http://pandodaily.com/2013/07/04/is-mayer-aiming-for-a-turnaround-of-the-stock-or-a-turnaround-of-the-business/

Don't blow it Marissa!

WRT founders, that'd be a fun Summer (Gapminder) project.  Figure out how much the company was bought for versus how long the founders stayed.  

• List of mergers and acquisitions by Google
• List of mergers and acquisitions by Apple
• List of mergers and acquisitions by Facebook
• List of mergers and acquisitions by Microsoft
• List of mergers and acquisitions by Yahoo!

There have been notable examples for Google where the founders stayed and the product thrived: Android, YouTube, many of the search companies they bought.

Tumblr's founder will definitely stay with Tumblr. 

There is definitely a method to the madness. It's basically the Google's M&A strategy, which makes perfect sense coming from Marissa. Google took a bunch of companies that were kind of cool on their own and combined them with Google's scale to real create value. See Keyhole, Android, Urchin, Applied Semantics, etc. Now are they executing well against that strategy? I guess we'll find out.

edit: To clarify, most have obviously been acqui-hires, which is a smart use of that pile of cash. But some of the acquisitions, big (Tumblr) and small (Big Noggins), are highly complimentary and could really benefit from the leverage of Yahoo's existing strengths.