That being said, we see many people adding their videos to youtube, vimeo, and hosting them with Wistia. YouTube is the worlds biggest video search engine so it's a no brainer. But if you're a business, the key is understanding who is watching your videos on your own site and how they're watching them.
We also see many other people doing much more than just hosting video. You can see many of the other sharing uses here: http://wistia.com/product/tour