Downloading and streaming video is one of the most resource intensive things you can do on the Internet, and your average web hosting account is not set up to effectively deliver video content to visitors. Not only will you slow down the web server your site is running on, your website visitors will have a horrible experience trying to watch your video. To solve this problem I would recommend hosting your videos on Amazon S3. Rather than trying to explain what exactly Amazon S3 is and why it is a cost effective solution for hosting videos, check out this article on Wikipedia: http://en.wikipedia.org/wiki/Amazon_S3