Forrester presents several ideas we haven't touched on squarely in this discussion so far:
With the advent of tablets and smart devices, it's critical you understand how your site appears across those experiences... Today, many sites sense if the visitor is on a mobile device and pivot to the m. version of the site. Trouble is, many of those experiences sacrifice showing some content for a sleeker design. This can kill your credibility with visitors.
Marking up your content not only helps us understand the content better, but it also helps you in the SERPs. As rich features become more commonplace in the search results, it's this marked up content that will be included. Recipes are a great example of this.
User Experience & Social
If you haven't invested in usability testing, it's worth it. Usability testing can be eye opening. It can help you see your site, content, navigational structure, etc. in an entirely new light.