Google Drive contains many Apps that can be directly embedded into Google Sites. Available from the "Insert > [Google] - Drive" Menu you have :
| Google Drive forms can be also used for survey contact or trigger advanced Cloud scripting via Google Apps Script etc.. | Spreadsheet embedded in Google sites can be edited directly this can useful when creating and maintenance through Google Sites. Sharing files via a Folder in Google drive , which then can be visible to a selective audience or even made public. Permissions can be set both on Google Drive and on Google Sites. |