Old school chats and forums dealt with that with special limited markup language for formatting and embedding images or other special elements like youtube vide

Old school chats and forums dealt with that with special limited markup language for formatting and embedding images or other special elements like youtube videos. Everything outside the limited markup options was treated as text with the replacement of < and > to HTML entities < and > meant to display HTML special characters in text. It was called BBcode, if I recall correctly. It looked something like that: [b]bold[/b] [i]italic[/i] [img]example.com/image.jpg[/img] [youtube]youtube.com/watch?v=someVideo[/youtube]