Per the newsletter I got from SMF for free: We have added support for autoembeding of video clips from popular video sharing sites posted below.
How it works you post a link to a video from one of the supported sites and the video player will automatically be added to the post so the users will not leave your forums.
Currently supported sites:
Facebook, Metacafe, Youtube, Vimeo, College Humor, Google Video, Veoh, Youku, USteam.tv, Rutube, Novamov, MyVideo.de, LiveLeak, Sevenload, Gametrailers, Funnyordie.com, Mevio, Crackle, justin.tv, SchoolTube, MySpace, Mefeedia, DailyMotion, Clipfish.de, Goear, Clipmoon, Stagevu, Mail.ru, Twitvid, Trtube, MegaVideo, BlogTV, VH1, BET, Espn, CNN iReport, PBS, Stream.cz, TNT, Comedy Central, BlogDumpsVideo, Reuters, MarketNewsVideo, Clipsyndicate, NyTimes, Clipshack, Mpora, Izlesene.com, Rambler.ru, Tangle.com