As you well know, it's extremely important to have the proper site architecture, technical requirements, and site infrastructure which is important for the search engines. With that said, I've found that most web developers are just that – web programmers who may not know the full effect of their core SEO strategies or marketing strategies. Most web programmers that I've worked with understand their jobs and their roles in the company very well and quite simply are unaware of the latest SEO trends or search algorithms and how they play a vital role to the search engine rankings of my client's website. Being able to work directly with these technical savvy professionals is a core requirement for any SEO firm or consultant that you bring on to help you with SEO. Keep these ideas in mind when trying to communicate with these types of people.