GOOG buying TWTR would be something expected. AMZN buying TWTR would be a complete surprise for everyone. When Amazon enters a vertical the market reacts and Amazon ends up buying stuff for free — like Whole Foods. Read my thesis below.
Amazon has grown to what it is today through it’s ecommerce business. Google did through it’s search business. While both companies have expanded their offerings, only Google owns a social business. And I’m speaking of YouTube and not Google+. Social is where the people are. So this means eyeballs, which means money from advertising and brand awareness.
On the other hand Amazon doesn’t have any returns from advertisers as it never looked at this market before. Maybe Jeff Bezos’s purchase of the WSJ will give him some experience with that. But print is dying and news is spread throughout social. So an investment in the second best (since FB is too big) would definitely help Amazon diversify its portfolio. Remember its Amazon that purchased Twitch after all.
Amazon would be able to expand its ecommerce know-how to social. We already see how well this works by looking at what Venmo is becoming. Well, Twitter is an even bigger opportunity as it has the social aspect already figured out. :-)