The links (url) that you shorten via this site may being seen by others. Indeed, it has been shown (Gone in Six Characters - Short URLs Considered Harmful for Cloud Services) that it is possible to "guess" the Shortcuts (against which we can do nothing) and thus to obtain the link information. If the link leads to unsecured confidential information by the target site, these data will be accessible. We draw your attention to this point before entering a link to a free Shortcut.
In response to this problem we have implemented the ability to indicate the link as "Private", so it will be accessible to the sole owner of the link. This service is linked to Premium Shortcuts and can not be set to the free Shortcuts, by nature open to all.