Chaos right now all over the YouTube platform as about 29K videos' titles and descriptions have been replaced with the following: "OurMine Are Back!... ( Read the description ) Hey, it's OurMine don't worry we are just testing your security, please contact us for more information" plus a website link and and an email address.
See for yourself: type "OurMine Are Back" in YouTube's search bar, then look at the number of results...
Just, WOW ;)
Update: it looks like many of the hacked accounts are celebrity/quasi-celebrity/verified youtubers...
Update #2: found some info here @ https://www.reddit.com/r/h3h3productions/comments/62vzxx/hacked_by_ourmine/
Update #3: it's all over Twitter already > https://twitter.com/search?f=tweets&vertical=default&q=%23ourmine&src=typd