Awesome Andy Kessler provides an actual argument for this, and it's basically new hotness:
So why bother buying YouTube? Is this a sign of strength ("we bought them because we can turn anything into gold") or weakness (like, say, Ebay buying Skype as their auction franchise weakens) or desparation (Excite merging with AtHome). It makes a difference. On the surface, this looks like a deal from strength - video is the next frontier on the Internet, blah, blah. But really, did Google want to do it or have to do it?
Despite continued growth, Google has hinted at a few signs of weakness. One is their huge capital spending to build datacenters and servers and bandwidth capacity, dinging their cash flow. I thought the search business scaled with much less investment. Maybe not.
And second, Google actually paid for traffic - $1 billion to Dell over 3 years for a crummy toolbar on Dell PCs. The numbers may work, but it's kind of like Hugh Grant paying for something he would get anyway. There may still be someone in Sheboygen who doesn't know about Google. Is search now such a commodity that Google needs to pay money to keep growing?
It gets better from there.