Updated (November 29th 2015): The referendum is to be held on april 6th 2016, GeenStijl just announced.
The Dutch electoral commission announced today that Dutch voters will head to the polling booth for a non-binding referendum on the EU-Ukraine Association Treaty. The treaty was approved by parliament but under a recently enacted Dutch law any piece of legislation approved by the legislature but not in force yet can be subject to a non-binding referendum if enough citizens request one. The commission said over 472,272 signatures were collected to request this referendum, of which 427,939 were valid, 127,939 more than the 300,000 required by the law.
The EU-Ukraine Association Treaty was the first piece of legislation on which a referendum could be requested. Dutch weblog GeenStijl.nl in tandem with political organizations "Citizens' Committee for the EU" and the "Forum for Democracy" were the first ones to try and use this law to force a referendum. They co-operated under the ad-hoc name 'GeenPeil.nl' and quickly built up a large volunteer-based ground operation to try and meet all the conditions imposed by the referendum law.
The first condition is that 10,000 citizens must submit an inital referendum request via a paper form mailed within four weeks of the contested law being approved in parliament. If those forms are deemed valid, a second six week period starts during which 300,000 paper signatures need to be collected and sent in.
The GeenPeil campaign focussed more on the lack of democratic accountability within the EU than on the contents of the actual treaty (even though it did receive some attention). Many Dutch voters are also deeply dissatisfied with the current cabinet, reflected in historically low numbers in recent opinion polls.
On August 13th the electoral commission announced it had received 13,480 valid initial referendum request forms. On september 15th GeenPeil claimed to have collected 451,666 signatures via digital means plus an unknown number on paper. These signatures stil had to be verified by the Dutch electoral commission though. Today the commission announced it had received 427,939 valid signatures.
By law, a referendum now has to take place within six months. If over 30% of the voters show up it will be considered valid. The results of the referendum are non-binding. It is widely assumed the results will be interpreted as a popularity test of the European Union and the Dutch cabinet. GeenStijl.nl already announced they will now start campaigning for a high turnout only, not taking a side for or against the treaty.