Re: googe drive comment

I would like to ask a further question to this topic googe drive comment

I followed [private information removed by moderator] advice to always upload and rename my files on Google drive. But when I comment a lot, this isn't really comfortable, so I got interested in the 2nd suggested possibility to use the free Acrobat.com cloud storage. Is https://cloud.acrobat.com/ the right url to use it? I have the feeling that I can only share files but no folders and that I cannot share them in a way that I see the comments of the others users.

Does anybody know a free (at least for students) cloud service, that enables a group of users to comment pdfs in a shared folder, so that every group-member can see the comments made by the other members?