Aqua, there are only so many ways to make your posts both visible and hidden. One way is by interacting with the forum enough to get to Tier Level 3 (TL3), which gives Lounge access. Lounge access (and the posts in it) are only visible by other TL3’s. Google does not index or access these threads.
The other way is to make your post unlisted, which means it doesn’t show up in the forum and someone has to have the link to that an example of that is the Ritual Bloodletting thread, which has an invite thread and the “real” thread that is hidden, but not secret.
The only other way is a Private Message, which no one has when they first start out.
If you feel these options may meet your needs, then please do an introduction in the thread here