From VIMEO's Terms and Conditions.
"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."
Pretty aggressive terms by anyones standards. I've had HDV footage ripped from websites and used without permission (so I don't post it now), but I had not realised that by posting to sites such as VIMEO you are actually giving them full permission to use your work anyway they see fit including the sub licensing and using your footage in derivative works without any compensation to you. Just a heads up for anyone that could be potentially worried.
Cheers, Simon