tedster - 5:21 pm on Mar 25, 2011 (gmt 0)
Lots of ways to introduce canonical errors, too - see [webmasterworld.com...]
I really like the canonical link tag as protection against all of them - even though I handle as many as possible on my own server. However, errors in the canonical tag can also create a disaster so again, technical precision. When the technical side is nailed down securely, domain moves can be relatively painless these days.