[1123581321]

They use hashes of known material, and in some cases, image recognition technology for more detailed review.

Files that are shared receive more attention. This helps since most files on Dropbox aren't shared. A file-sharing application would not be able to use that filter, obviously.

[DanPir]

Do you think would work the concept that the platform would not be responsible for the files uploaded?

[1123581321]

Probably would at first. Go ahead and build it!

[DanPir]

I am not sure how many "competitors" there are already

[1123581321]

My opinion is that file sending is a market that can support a lot of competitors. Maybe start with a basic prototype and see if you want to continue.