Nikolai Mavrenkov already created a good description of the problem on Stack Overflow: http://stackoverflow.com/questions/36893449/textarea-placeholder-isnt-shown-in-ie-11-being-rendered-using-react

I just can confirm it breaks in IE11, but works in IE10 (and other browsers) with React v15.0.2.

mountComponent: function(
    transaction,
    hostParent,
    hostContainerInfo,
    context
  ) {
    this._rootNodeID = globalIdCounter++;
    this._domID = hostContainerInfo._idCounter++;
    this._hostParent = hostParent;
    this._hostContainerInfo = hostContainerInfo;
    var props = this._currentElement.props;
    switch (this._tag) {
      case 'audio':
      case 'form':
      case 'iframe':
      case 'img':
      case 'link':
      case 'object':
      case 'source':
      case 'video':
        this._wrapperState = {
          listeners: null,
        };
        transaction.getReactMountReady().enqueue(trapBubbledEventsLocal, this);
        break;
      case 'input':
        ReactDOMInput.mountWrapper(this, props, hostParent);
        props = ReactDOMInput.getHostProps(this, props);
        transaction.getReactMountReady().enqueue(trackInputValue, this);
        transaction.getReactMountReady().enqueue(trapBubbledEventsLocal, this);