There is a good thread going on over at Search Engine Watch forums about outsourcing link building efforts and if you should or not. This question was asked by another SEO but its relevant to SEO clients as well. You never know when your SEO might be outsourcing such a crucial component of your campaign.
In years past we have outsourced our linking efforts only to be extremely disappointed. While we had good people working on the links from time to time overall the quality control was difficult to manage. Not only that, but link building should work in conjunction with the optimization efforts. With links being so important it doesn’t make sense to have a disconnect between that and the SEO efforts. Not when you’re going after quality links anyway.