It'll be like looking at portraits in Hogwarts or reading the Daily Prophet. Or MySpace back in 2005. We're not sure yet.
According to Mashable, Facebook had started rolling out profile videos to replace profile photos, which will make the most significant change to how Facebook looks since they introduced the timeline.
Comprised of seven-second looping clips, the videos will be similar to GIFs and Vines (although neither will be supported) and will only appear when you visit someone's profile page. A single selected frame from the video will act as the thumbnail in your feed as normal.
Per Mashable, profile videos are "part of an effort to help people further greater express their personalities and creativity on the site", and continues to feed into the world's narcissistic tendencies.
Unfortunately for us, the only users currently getting to play around with profile videos are those based in California and the UK, it is expected to be rolled out to other users in the near future if it proves popular (and we can't imagine it won't).