Alternative Informatics Association notice summarized what happened:
Internet shutdown operations have started in Turkey as of 1.30 am on November 4, 2016. This was right at the time when Selahatttin Demirtas, the co-president of HDP (Kurdish front Party) was detained in Diyarbakir. 14 other party members have been detained by the State with allegations regarding their links to the terror organizations. First twitter, then Facebook and following that WhatsApp and Instagram was blocked. At 9.00 am in the morning, access to Skype was also prevented. All blockages have been performed through Turkish telecom networks. WhatsApp access is occasionally possible via SatelliteNet at the moment (1.20 pm, Istanbul/Turkey time) All mobile service providers do not work in compatibility with services like Telegram. OpenVpn does not provide perpetual access, either. As of 1.22 pm, full blockage has been lifted off Twitter and Facebook, but throttling continues. Main internet service backbone in Turkey, Turkish Telecom Network (TTnet) is still shut down (November 4, 2016; 1.25 pm Istanbul/Turkey time zone).
1st time a Turkish official confirms that internet shutdown is ordered by the government.
PM Yıldırım: It will end when the threat is over. https://t.co/94yTQ0jvd7
— efe kerem sözeri (@efekerem) November 4, 2016