Basically, Yahoo is losing money with tumblr and given its history with fandom based sites, there is a good chance tumblr might close soon. It doesn’t look like Yahoo have given warning for this kind of thing in the past, so to be safe I would prepare for closure (saving posts, making sure you will still be able to reach people you talk to etc outwith the site). I am just sad because this is a community and the thought of losing you all, of losing it, kills me.