(sorry if repeat, first post attempt got swallowed I think)
yes whisperspace! Lotta discussions happened about that and I paste the useful bit from the gdoc and give some background below, but basically TL;DR at the end of the post, in the post itself, use [ code ]....[ /code ]
(with spaces removed) for whisperspace, with ... replaced with the text you want.
From the doc:
There are two kinds of tags on Hubzilla:
the ‘categories’ field underneath the heading input box of the posting screen. Text input here ends up appearing highlighted yellow under the post, and also populates a permanent list on your home channel on the left. These tags do NOT carry over when the post is shared.
Hashtags within the body of the post itself, which populate your own channel tag cloud and the instance tag cloud, and which DO carry over when the post is shared.
Both these tags are useful, but neither works well for whisperspace. The hashtag strategy populate your channel tag cloud and the network tag cloud, so whisperspace tags will complicate both those too. As for the categories tags, those don’t carry over when a post is shared! Only in-post text is transferred (and also, the highlighted yellow is about as far from whisper as an aesthetic as you can get ;)
So how to do whisperspace on Hubzilla?
So far the option that has received widest support on Hubzilla is to use
[ code ]....[ /code ] [without spaces] for whisperspace at the end of a post. More options are in development!
It was a good debate, and a few different suggestions were made. Some put whisperspace at the top; some used bright colors some didnt; some transferred the text when reblogged and some didnt. I went off and got Chad to weigh in offline because of being Undisputed Master of the Whisperspace Arts who confirmed yes at the end, so people don't have to scroll back up to see it after reading the post.