they do have youtube plugins. Search in the mods section of official SMF forum. Its the code that users can simply paste the youtube link and it'll auto display video. and alternatively you can embed ANY codes in SMF by using this code in bulletin [ html ]code[ / html ] (without spaces) code can be any thing even adsense ads! youtube embed ad or any html codes you wish to display say you put youtube embed code via that, it'll show video. Make sure you enable BB code by going to "post and topics" > "settings" > "allowed codes" HTML: