Who knew there's a [ PHP]-tag?
You made me curious, turns out there is also a [html] tag (no cute coloring though?).
<input type="text" name="subject" value="Re: Hidden pages/ features on the forum" tabindex="1" size="80" maxlength="80">
And here is a actually good one:
[nobbc]xxx[/nobbc]
So you can write the bbcode tag as it is:
bold here[b]no bold here[/b]
[b]bold here[/b]
[nobbc][b]no bold here[/b][/nobbc]