One thing we should know about this companies like facebook and twitter is that what have kept them in the top is the ability to see a new technology and embrace it in other to improve their platform and getting more people on-board, they know that blockchain is the technology of the future and they are not ready to miss out of it because if they miss out, in few years to come they might not be relevant as they are now in the society and world at large.

Merchants and corporate giants first may adopt blockchain technology which might move toward bitcoin over the course of time for sure. I mean now facebook, twitter and JP morgon kind of big corporate are announcing having their own blokchain based coins and this may help spreading awareness on cryptos which will end up in mass adoption and then main stream hitting.

You have to understand first what is blockchain technology and how it will benefit both online and offline platforms, businesses and industries then only we will know why everything is adopting this new tech soon you will hear more and more online giants switching to blockchain. I think we should not try to find conspiracy theories behind each news.

The answer is simple, no one want to be left out on what blockchain offers. For someone or a platform to grow the platform must be ready to flow with trending technologies. So if they refuse getting involved one day, they will be leftout and out of business.

Because the world is changing from physical companies to internet companies and now to blockchain companies. It is the natural development. 
I like it because when internet was created and first companies were created on the internet, I was so young. But now I can be a part of it.

The simple answer for this is that they want to use the advantages of blockchain technology and they are realizing it`s potential. They also want a piece of the pie as they have billions of users and do not want others to take this advantage from them.