To manage the files you have shared, click on the "Manage Sharing" option on the Web Application toolbar. This will take you to the 'Sharing Management' interface that lists the share date, file name, and link to all the files you have shared.
A description of each of the sharing management actions is listed below.
1) Protect or un-protect your file: Un-protect a file that was previously protected and your share recipients will no longer need to enter a password to access the file. Protect a file that was previously un-protected and create a password that your share recipients will be required to enter before accessing the file.
2) Activity Log: Shows activity that has been associated with your file.
3) Tweet: Allows you to login to your Twitter account and tweet your shared content to your followers.
4) Share or un-share your file: Share a file that was previously un-shared, which will re-activate the share link associated with the file. Un-share a file that you previously shared and it will deactivate the share link so that your recipients can no longer access the file.
5) Expire on: Set a date for your share link to expire.