SeeToo is a new service, currently in private beta, that lets you show your video to one other person - in real time. Just install a client, choose a video from your PC, and send a link to the person you want to share the video with. When they click the link, they'll go to a web page showing your movie and you can both watch it at the same time, and chat in a little chat window below the video.
SeeToo facilitates the whole thing, but doesn't store your video on a server. So you're not actually leaving a video on the internet for the whole world to find. Of course, if you send the link to your friend and then turn your computer off, they'll also be unable to watch the video.
The company plans to launch a public beta by the end of the year.