user47935: I understand that there is no central authority on Bitcoin, but I can't understand who takes decisions on "forking" the blockchain.
Here it was mentioned that the "Bitcoin community voted"—how did that happen? Who is the community? I assume anyone? If so, how can one vote? 
I was reading about a hard-fork coming on 16th of November and I don't really understand how that works.

user63397: No-one decides literally for everyone. Miners make the decision to exploit one proposal rather than another one, so whenever miners disagree and don't follow one protocol to around 100% then a fork happens. 
In this case (of B2X) it is the proposal of Segwit2x that will or will not be followed. 

47935: <p>I understand that there is no central authority on Bitcoin, but I can't understand who takes decisions on "forking" the blockchain.</p>

<p><a href="https://bitcoin.stackexchange.com/a/57497/47935">Here</a> it was mentioned that the "Bitcoin community voted"—how did that happen? Who is the community? I assume anyone? If so, how can one vote? </p>

<p>I was reading about a <a href="http://www.zerohedge.com/news/2017-10-24/here-comes-bitcoin-gold-bitcoin-rally-falters-latest-blockchain-hard-fork" rel="nofollow noreferrer">hard-fork coming on 16th of November</a> and I don't really understand how that works.</p>
 63397: <p>No-one decides literally for everyone. Miners make the decision to exploit one proposal rather than another one, so whenever miners disagree and don't follow one protocol to around 100% then a fork happens. </p>

<p>In this case (of B2X) it is the proposal of Segwit2x that will or will not be followed. </p>
