It's about managing investor sentiment. Core profitability of their ad business (as indicated by CPC) has been declining for I think 9 or 10 quarters in a row now? They're aggressively monetizing all their services and products because of this to keep driving aggregate clicks up. "We'll make it up in volume"
They need shiny baubles to dangle in front of investors in the absence of creating real new markets and businesses that generate cash flow. It's not just for investors either. They're attempting to be perceived to be an innovative company in the eyes of their various stakeholders (employees, potential employees, tech press, the general public, regulators, etc.) even though they're pretty much the new Microsoft in terms of milking their one hit (advertising).
Funny enough, Google's core business is being disrupted by the mobile revolution ushered in by Apple (you won't read that particular narrative in the tech/financial press because Google X and other high-profile "moon shots" have been effective in accomplishing the PR objective). Android was a completely defensive move about making sure the erosion to that business was limited and that they'd have a slice of the advertising pie even if it's fundamentally less rewarding than desktop advertising. If Google had attempted to sell Android it would have never been as successful, so there was no choice, it was purely about staunching the bleeding.
This is why Google has been so acquisitive for so many years; they're desperately searching for new businesses that make money (and also clearing the market of anything that could threaten their existing one). The tech media interprets this as being "bold" and "innovative" (which really doesn't make any sense when you think about it) but it's really out of fear and desperation. Companies that have defensible moats around their business don't need to overpay or rush into deals. The media cheerleads it because it gives them something to write about and the resulting boom in Silicon Valley has flowed to them as well. VCs cheerlead it because they rely on these insecure companies to provide ample exits for their portfolio companies at lofty valuations (https://twitter.com/cdixon/status/427602474086584320). Follow Marc Andreessen on Twitter to see him try to justify valuations in technology and dispel any comparisons to the Dot Com boom. Facebook does this as well, but fortunately for them they have a stock that is insanely overvalued which allows Mark Zuckerberg to use it as currency. Google's valuation isn't as generous, but more importantly these acquisitions have been diluting Larry and Sergei's controlling interest (something they recently rectified with a new class of shares). So I'm sure they'll be matching Facebook's pace in no time.
It is perfectly reasonable to seek out other revenue streams. It is still a land grab. There are many other megatech companies that aren't innovating or acquiring and are slowly dying. The "tech platform" evolves every 10-20 years. Innovate or die. We already talk about the Internet of things. Mobile apps and mobile access are clearly eclipsing the PC. Odds are the next Facebook or Google starts as some mobile app not yet invented.
how do they plan that? they would want the technology news to come before the result news to soften the landing? or they would do it after to try to cheer up the stock?
There are billions of dollars at stake. They know what the estimates are the whole time, and they have a pretty good idea for weeks/months on whether or not they are going to hit them. They would be borderline insane to not have PR plans in place. It would be naive to think otherwise.
