appears out of the ether for a fleeting moment
This link should help answer a lot of questions about the forum ranks, syntax, and requirements.
As far as I’m aware, only rank 3 holds the privilege to post images and clickable links at will. Otherwise, links must come from approved sources(such as Blizzard sites, YouTube, WoWhead, etc.) or placed between a pair of ` marks so the text isn’t clickable(text will need to be copy/pasted instead). Rank 3, once attained, will lapse if forum activity does not continue to meet high enough thresholds, and I believe is permanently removed if you’re flagged enough times or disciplined otherwise by Blizzard.