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.
Softros LAN messenger - LAN messenger for an internal office chat for home or business users. It does not require a server and is very easy to install and use. It supports personal chats, group chats, message brodcasting, files transfer and remote desktop access.
Dropbox - Online Sync and File Sharing
MyChat - Secure instant messenger for any network
Google Drive - Access and sync your files anywhere
BORGChat - BORGChat is a LAN messaging software program.
Mega - Secure File Storage and collaboration