Don't know how it actually works, but my bet it's in the format:
</color_tag>your_colored_text
the </FFFF00> part is there to switch color back to yellow as it is. If you don't append it, all the text following color tag will be in that color.
Here
[Only registered and activated users can see links. Click Here To Register...] are all codes you should be able to use safelly.
So, if I make </FF33FF>Kick </0000FF>da </FF0000>Bunny </000000>...MrBlacky
it would look like
Kick da Bunny ...MrBlacky
[/1/0=AuctionItem] has something to do either with:
a) hyperlinks
b) text decorations, like
bold or
underline. Try mixing them and see what comes out (whisper yourself)
may be both