+Remote mentions are delivered using the OStatus protocol.
+This protocol is used by Friendica and GNU Social and several other systems, but is not currently implemented in Diaspora.
+As the OStatus protocol allows this Friendica user can be @-mentioned by users from platforms using this protocol in conversations if the "Enable OStatus support" is activated on the Friendica node.
+These @-mentions wont be blocked, even if there is no relationship between the sender and the receiver of the message.
+
+Friendica makes no distinction between people and forums for the purpose of tagging.
+(Some other networks use !forum to indicate a forum.)
+
+If you sort your contacts into groups, you cannot @-mention these groups.
+But you can select the group in the access control when creating a new posting, to allow (or disallow) a certain group of people to see the posting.
+See [Groups and Privacy](help/Groups-and-Privacy) for more details about grouping your contacts.