Quote from the words of Datum blog:
"After releasing the alpha version of our app for the pre-sale community, we have now a functioning prototype of Datums Dashboard, which tracks the activities on our network."
You just can use this alpha version of Datum app if you were joined pre-sale of Datum in past time. Else, you do not have permission to use this app at now.
Did they say something about being available to normal users before ICO? I dont see the point of them not releasing it to everyone since it will do good for investments.