i have seen some sites that once you come across them a particular video starts play for about a minute without streaming the video just starts playing right away (mostly adult ads not youtube). i would like to know if this is a particular type of video format or is it that the whole video was embedded into the website or what exactly ? i just can't figure out how its done but i've seen it happen most times.
You can do it with youtube embedded code. For example, starting with part of embedded code for youtube: <object width="425" height="344"><param name="movie" value="http://www.youtube.com/v/Qf7-877qkN0?hl=en&fs=1"> Add the extra red text shown below: <object width="425" height="344"><param name="movie" value="http://www.youtube.com/v/Qf7-877qkN0?hl=en&fs&autoplay=1"> Then when the page with this youtube code opens, your video should start playing straight away - it will play the whole video, but you can always split one you want to play in two so that it just plays the intro.