Mr Cutts clears up any confusion in this video regarding the rel=”canonical” tag working cross domains.
This is a really useful tool now for webmaster, consultants and marketing agencies alike.
Recently, I used this cross domain rel=”canonical” for a social competition for an e-commerce client as part of a wider SEO campaign. The twitter driven competition referenced the competition page in which a rel=”canonical” pointed to the relevant target URL we wished to target.
The hope was that Google would see the relevancy of the rel=”canonical” tag and believe it was there for relevancy and not for any underhand techniques.
This was partly an experiment to see whether the rel=”canonical” had much effect, unfortunately we didn’t see a move in the ranking, however the video cited seems to suggest that a rel=”canonical” with relevancy should work.