<< What the hell is a .smi?? >>
"SMIL, or synchronized multimedia integration language, is an XML-based language that essentially pieces together your media files in the order that you would like them to appear and combines them into a single stream.
RealNetworks has been a pioneer in developing SMIL for the Web, and has created proprietary formats for use within a SMIL script. These are RealText (.rt), RealPix (.rp), RealVideo, RealAudio (.rm), and RealFlash. By incorporating SMIL scripts into your RealMedia files, you'll give your site a whole new level of usability.
You may be happy with the current content on your page and are saying, "I use MP3 now, why should I use SMIL instead?" When you encode audio into the MP3 format using the standard 44.1 kHz sampling rate, the general output is around 1 Mb per minute of music. That is a lot of bytes to download if your users have a 56k modem connection. By using SMIL, your content is streamed to the user. This gives them instant gratification, and they'll have more time to surf around the rest of your site now that they aren't waiting for an MP3 to download." - Webmonkey