Wouldn't it be great if Facebook let you post short Profile Videos?
Hands down, one of the most popular features of Facebook is each member's Profile Photo. Almost everyone has one, and it's the first thing anyone sees when they look at your account, so why not take it to the next level? Why not allow people to post a quick 10 second Profile Video that lets the member express themselves in ways that can't be done with just a photo alone?
In order to keep things simple, I think it would be a good idea to limit the video to 10 seconds or less, just like a Vine video. That gives you just enough time to say hello, and maybe show off something and say a few words.
If a picture says a thousand words, a video says far more than that.