Good Grief! Facebook just got slapped silly by it's users for the exact same thing.
By submitting your Submission to VIMEO, you hereby grant VIMEO and its affiliates, successors and assigns a worldwide, perpetual, non-exclusive, irrevocable, royalty-free, sub-licensable (through multiple tiers) and transferable license (with a right to create derivative works) to use, copy, transmit or otherwise distribute, perform, modify, incorporate into other works, publicly perform and display your Submission or any portion thereof, in or through any medium, whether now known or hereafter created. VIMEO shall be entitled to unrestricted use of any Submission for any purpose whatsoever, commercial or otherwise, without compensation to the submitter.
Source: Sean Locke (read his article for other problems you can run into if you sell stock photos or moving images...I'm glad I never put anything on my Vimeo account). Hat Tip: Scobliezer (via twitter)