I tried to limit the tags to what the DSi could show. It has support for underlines, so I allow < u >. There is no support for bold, but it can do the text-shadow style, so I use that to simulate < b >. The carriage return and linefeed automatically convert to < br / >. The DSi has no support for < sub >, < sup >, < i >, and several font sizes, so < font > is stripped. Links get killed to prevent link spamming.