It is completely fine to upload videos to YouTube for commercial purposes, with links to your site, etc.
From the YouTube TOS:
http://www.youtube.com/t/terms
Prohibited commercial uses do not include:
- uploading an original video to YouTube, or maintaining an original channel on YouTube, to promote your business or artistic enterprise;
- showing YouTube videos through the Embeddable Player on an ad-enabled blog or website, subject to the advertising restrictions set forth above in Section 4.D;
- or any use that YouTube expressly authorizes in writing.
And given this: http://www.google.com/support/youtube/bin/answer.py?answer=71011&hl=en-US, it appears to be fine even to embed those videos for commercial (non-ad) usage.
We've updated our Terms of Use to
clarify what kinds of uses of the
website and the YouTube Embeddable
Player are permitted.
We don't want to
discourage you from putting the
occasional YouTube video in your blog
to comment on it or show your readers
a video that you like, even if you
have general-purpose ads somewhere on
your blog.
We will, however, enforce
our Terms of Use against, say, a
website that does nothing more than
aggregate a bunch of embedded YouTube
videos and intentionally tries to
generate ad revenue from them.
Vimeo however appears to be a different story:
Vimeo is intended for non-commercial use. By using the Site, you agree to abide by these Terms of Service.
Facebook I believe is fine, as many of the largest brands in the world use it for promotion, such as Coca Cola and Pepsi - so I think yours would be fine.
Hope this helps.