Thanks for the feedback!

Generally when sharing you send a link like "sandstorm.company.com/share/xh37vmw0h5276mj7h5eh" -- the random hostname you quote is actually an implementation detail that you weren't meant to see. :)

Once a user has opened a sharing link once, the grain will appear in their "shared with me" list, so they can find it again by going to sandstorm.company.com. We will soon support sharing by other mechanisms that don't involve sending a secret link, too.