The "secret" video lives of facebookers: "Oh, and it's easy to add video to your own profile and because you can make it so that just your Facebook friends can see your video it's pretty safe to play around and post some lame video that, if it were on YouTube might just go viral and get you onto the nightly news."
And its not just your own videos. Your friends can share your videos too. For instance, I shared Roberts video as a test, and it shows up on my profile. I'm assuming one of my friends could take Roberts video and share it, even though they wouldn't be Roberts friend. Potential for one of those viral videos.