For hosting common files it's ok. Also it is on Android too do, great to transfer files between your Windows and your phone. But if you want better security you have to subscribe a monthly offer.
Bitrix24 - Bitrix24 is a free (for small businesses) social enterprise platform. It is a united work space which handles the many aspects of daily operations and tasks. Create your own social intranet in minutes!
Dropbox - Online Sync and File Sharing
LinkedIn Premium - LinkedIn is a social network helping brands and professionals to connect, identify sales prospects, hire talent, and promote their business.
Google Drive - Access and sync your files anywhere
Salesforce Chatter - Salesforce Chatter provides a suite of collaboration features to any application built on Force.com.
Mega - Secure File Storage and collaboration