How-To Geek erklärt unter dem Titel «How to Comment on PDFs (or Any Other File) in Google Drive», wie man irgendein Dokument in Google Drive kommentieren kann (via Researchbuzz: Firehose):
«You might already know that when sharing documents using Google’s own office apps you can leave comments to make collaboration easy. But did you know Google Drive offers the same comment feature for virtually any file, not just Google documents?»