The first true social video sharing service is Canadian-made Keek. It launched about two years ago and has since been made cross-platform (available on iOS, Android, and BlackBerry 10 as well), which helped it grow to a strong 50 million users. Two days ago, Keek announced that they would be the first social video sharing service to launch on the Windows Phone 8 platform, offering those users' the ability to to upload and share footage recorded on their smartphones. Keek gained popularity earlier this year, prior to the Vine's and Instagram videos of the world, when it became the first celebrity-used social video sharing service.
Download Keek free via the Windows Phone marketplace here.