[y]search term[/y] - will turn your term into a linked Yahoo search for that term.
[m]search term[/m] - will turn your term into a linked MSN search for that term.
[aj]search term[/aj] - will turn your term into a linked Ask Jeeves search for that term.
[o]search term[/o] - will link you to the Overture search term tool
[hr]search term[/hr] - will turn your term into a linked High Rankings Forum search for that term on Google.
[search=page rank]whatever[/search]- will do a forum search for whatever term is in the bracket.
[hl=yellow]Highlight[/hl] - will highlight your words with the color that you input
[hld=blue]Dark Highlight[/htd] - will make the text white and highlight the color that you choose.
[offtopic]random thought[/offtopic]- will outline the content and add an "OFFTOPIC" header to it.
They might be useful when giving examples.