When CAN you advertise? - When it is clearly and explicitly stated by the creator/host/owner of the project/studio/profile that you CAN advertise in that specific space. - If it's your project, studio, or your profile, you always CAN advertise. When CAN'T you advertise? - When the creator/host/owner of the project/studio/profile says that you CANNOT advertise in that specific space. - When the creator/host/owner of the project/studio/profiles DOES NOT give permission or say to not advertise; they don't say anything about it
TL;DR - Advertising is only allowed if the creator says it is, or if you're the creator. Evidence: @achouse (Scratch Team Member): https://scratch.mit.edu/projects/1146091122/#comments-555982031 "advertisements are not allowed in project comments by default. The creator doesn't need to say "no advertisements" for this to apply." Scratch wiki: https://en.scratch-wiki.info/wiki/List_of_Controversial_Topics_on_Scratch#Advertising "The Scratch Team has stated that advertising is okay in one's own spaces, for example one's own projects and studios, but advertising is not okay in another person's space, unless they give direct permission." Advertising without permission also breaks the "Give Helpful Feedback" guideline.