Where it is:

What it is: A web service that allows people to upload only to a selected folder on Google drive, Dropbox, or OneDrive

How does it work:

Teacher: After creating the account, select your cloud service, the folder, and password. The password is passed on to your users to direct the file to the proper location. Other options include receiving an email when a file is uploaded, and having multiple addresses for uploading, for example one for each class period.

Student: Goto, enter the password to permit an upload, then either drag-and-drop the file into the upload box, or use a file browser to locate and select the file.

What data do they collect: Information you supply such as your email address, IP address, any communications you have with them, any info that Google Analytics may collect.

How do they support the site: As this point, partly by donations of users, and also by offering custom branded pages to those who don't want the Drop-It-To-Me logos showing.

Additional Notes: Instructions on the site are scant. Since you have given them the ability to read/write files to a particular section of your web drive, in theory, they could read anything in that folder.