Turkey is in a really weird place. On the one hand, Erdogan is a corrupt tyrant who has done some inexcusably horrible things. On the other hand, he has thoroughly cleaned the cemaat infestation. For the record, cemaat refers to people loyal to a man named Fethullah Gulen, who is a radical Islamist and a very controversial figure in Turkey. You can read more about him here:
http://www.city-journal.org/html/who-fethullah-g%C3%BClen-13...
Anyway, Internet blockages like this usually precede widespread police operations. Based on what I can gather from Turkish newspapers right now, it looks like HDP headquarters is being raided by the police as part of a terror investigation (which is kind of a big deal). HDP is a pro-Kurdish, pro-minority party that got a lot of votes in the last election and prevented Erdogan's AKP from reaching parliamentary majority.