Cinemagraphs have been around for a while and with the rise of auto play videos they are becoming more common. A cinemagraph is looping gif or video (I've read plenty of arguments over which it is) where the majority of the image is static with a small section moving. You can expect to see a lot more of them popping up on sites like Facebook as brands battle for their audience's attention. Personally I think they are great if a little fiddly to create.
If you want to find out how to make a cinemagraph check out this handy video.