What can I do with conversations?
Conversations are a way for you to collaborate with other people by posting comments and discussing topics in real time.
If you want to discuss a specific document or folder, you can start a conversation about that item. When a conversation is started for a file or folder, members of the folder can post comments that are visible to all the members of the folder. This means an entire team can view and comment about a folder or files. Anyone who is a member of a folder can view a conversation or add posts to the conversation. It doesn’t matter what role a person has as a member of the folder. If a person can view the contents, the person can view the associated conversation. To give new access to someone to that conversation, you need to add the person as a member of the folder. If you remove someone as a member from the folder, they’ll also lose access to that conversation.
Or you can start an independent conversation about any topic you want. When using your web browser or mobile device, you can start a conversation and add members to it. They can post comments in the conversation and reply to comments from other members. They can also add documents to share with other people in the conversation.
You can also create private conversations or “direct messages.” This type of conversation is between you and one other person and no other people can view the contents of the conversation.
You can use hashtags (#) to add keywords to your conversations. A hashtag in a message designates a meaningful term or topic so it’s easy to group all content associated with that term or topic. You can reply to, edit, delete, and restore any comments you make. You can “like” any post or mark posts as un-read or read and you can flag comments to catch someone’s attention.
When a conversation is started about a file or folder, 
appears with the item, showing you that a conversation is active for that file or folder.