I guess maybe the restructuring from Google to Alphabet worked. The idea was based on Berkshire Hathaway, another company with unusual growth. (http://www.berkshirehathaway.com/letters/2017ltr.pdf)

that seems like a strange conclusion, since a huge majority of the revenue and growth is still coming from Google.

I think one of the advantages of that structure is the head of Google now just focuses on Google instead of trying to think about a dozen other businesses as well.

Indeed, focus is a great thing. Although weirdly enough, Android is still part of Google as well; you'd think that'd be a prime candidate to move alongside Google as its own venture.

The idea may be that android benefits a lot more from integration with other google products. Although I'm not sure on how inter-alphabet cooperation is going.

I wonder what's the idea behind google growth ... maybe android apps improvements got them more visits/ads

Patrick Pichette always had a saying internally that 20% is the magic number. If you can keep growing 20% YoY, investors will let you do whatever you want.

I fear the times when they can't achieve those 20% and the winds start to change massively.

I think a big part of it is how over the past few years, the internet has truly gone mainstream in a way that it hadn't prior, namely the ad spend online, is starting to catch up with the time spent online as compared to other platforms such as TV, print, ect.

I believe 2017 was the year online ad spending passed television.

A quick search, using these terms: digital ad spend surpasses tv, shows multiple sources confirm my belief.