File sharing sites such as dropbox make it very easy to share files. They also make it very easy to be hacked also. My first suggestion is if you have data that is sensitive be careful before putting it on a file sharing site such as this. If you do put on this site, make sure you have a strong password and you change the password every 90 days.
Also, some are starting to consider offering 2 factor authenication. If you have data that needs to be secure, you should enable the 2 factor authenication.