I used to open yobits site atleast once a day because there are some bitcoins and altcoins there i had and i keep checking the prices but after seeing your post i just saw there is some problem with the site.I hope its down only for some time and will be back again becuase i am holding my decent amount there.
As soon as the site comes online the first thing you do will be withdraw your funds from the exchange. Do not trust exchanges for keeping your bitcoins they can run at any time i honestly don't trust but i have some altcoins there and i will withdraw once the site comes online.