Your content cannot be taken down from the Hive blockchain. All contents will remain on the Hive blockchain as long as the Hive blockchain exists. However the owners are probably able to remove your contents from the front-ends. For example from hive.blog, from peakd.com. Just like there is censorship on the Steem blockchain, and the contents can be removed from Steemit and from SteemPeak, and probably from other front-ends. And there is censorship also in the Steemit communities, for example in @dcooperation. But the contents remain on the Steem blockchain as long as the Steem blockchain exists.