Consumer Barometer – Google’s Consumer Barometer provides insights into how consumers search and research product purchases – which is useful insight when it comes to creating content that targets those consumers.
Google Analytics – If you use Google Analytics, you have a goldmine of data available to you to inform your content marketing efforts. The keywords people are using to get to your website, for example, tell you what topics people are interested in and searching for.
Google Keyword Tool – Keyword research is a must for content planning and creation so your content can be optimized for the right keywords. Google’s AdWords Keyword Tool is one of the best (free) tools out there for determining which keywords to use, and also doing some competitive keyword analysis.
Buzzstream – BuzzStream is a platform that can be used for SEO link building and public relations. Using BuzzStream, you can look up keywords to find content about those topics and the influencers writing that content. This will not only help you with research, but also with generating additional content ideas.