I purchased this primarily to share a video with a friend of mine. The video is 415MB and is too large to be included in an email. I tried sharing it with my friend. I noted one thing that it is not shown on my shared list. I followed the directions given me in Dropbox sharing process. How can I know if the linke was sent to that email address or not? There should be actual instructions on how to use Dropbox sharing. Please reply!