Anyone have an idea what is happening to their margins by the way? Who is competing against the same ad dollars as Google (FB seems a bit different), if cost per click is going down, why?

I think they are like any other big industrial company.

They build out factories (datacenters, networks, etc) based on a projection of long-term growth. Once you start missing those growth targets, it's like compounded interest... the impact of a small miss in year 1 has a big impact on the year 5 bottom line.

They have a few issues IMO:

- The market is saturated... how many more tiny classified ads can you sell?

- The "less sophisticated" users who click on ads use Bing -- the Windows default.

- There are real competitors out there... Bing, Facebook, etc.

- They piss off their hardcore users too much. Google+: enough said.

Also, because mobile has less space for adword ads.

The explanation I'd heard was that more people are using mobile devices and ads are less effective there.

I would guess it's mobile/tablets. I rarely see tasteful advertising geared towards that space, and "regular" pages shown on a mobile phone force me to zoom in on content and scroll past ads.