Google to the World: “I’m Still Relevent Because I Show Tweets”
From now on, Tweets will be shown on Google’s SERP’s. And guess what, it will be shown before everything else:

Tweets on google: Wow now I can get all that spam in one place!
Basically, Google is saying to it’s users: “Hey guys come on over here: I got tweets too”. And it is also saying to SEOs and SMOs: “Hey guys I’m still relevant: even if you post your stuff on social media, you will need me to get people read them”.
Also, what Google is saying to everybody else: “Listen guys, I know you all worked hard to get your stuff on the top 5 spots of SERP’s, but listen, these social sites are killing me. If I don’t bring them traffic, I might not have any traffic myself. You goatta understand…”
My conclusion: bet on Facebook and Twitter cuz Google is a dinosaur already.