@M4TT, thats the old YouTube tag code from version 7.5.x. It is not mobile friendly and detects just 17 of the top 32 most common different YouTube URL variations. Follow the directions to upgrade to the 7.6.x Youtube REGEX strings, which can detect more than 32 of the most common YouTube variations. In addition, it will not break your forums for mobile users.

isaac @ id242.com // my forum @ CelicaHobby.com
a current developer of UBB.threads php forum software // 7.7.2 Progress Notes