seomoz.org. This week Rand interviews Tanya Vaughan, Global SEO Manager for Hewlett-Packard. As the head of SEO services and programs for such a large company, Tanya frequently works with outside SEO agencies to contract out services. She opens up to Rand about some of the most important things she looks for when sourcing an agency. This is valuable stuff to consider for both in-house folks who work with agencies frequently, or agency folks who want to know the best way to approach large clients like HP.