website terms of service

If a website's terms of service say that for anything you post to their site, you grant them a license to reuse republish etc. and I post a link to my content for which I hold the copyright, is that the same as actually posting the content?
For example if I made a post on a social media site about a new video I'm working on and I paste a link to the trailer on a vimeo page, does that grant the social media site all the rights that they would have if I actually embedded the video on their site directly?
Thanks