Google's "No Cost to You" Tools

Google Webmaster Tools -- The definitive tool enabling webmasters to diagnose Google search indexing issues, research keyword visibility (impressions, clicks, click-through rate, average position, position distribution), article popularity on Google search engine results pages (SERPs) and overall website speed.

Can help answer the questions: Why has my Google-referred traffic changed? What keywords trigger results for my content in Google? Where does my content rank (on average) in the SERPs? How does my Google visibility change over time?

Google External Keyword Tool -- External meaning available outside of Google AdWords, this tool provides invaluable keyword research information such as average competition, global monthly searches, local monthly searches, and local search trending. Somewhat dated now that Google Insights for Search has arrived (see below).

Can help answer the questions: What keywords are the most popular for websites in a given category? Which keywords are becoming more popular over time? Which keywords have a good balance of high search volume and low competition?

Google Analytics -- Arguably the most powerful tools you would ever need in order to maximize the ROI of your SEO campaigns are found in your web analytics software. It doesn't matter how much traffic you get from Google if 100 percent of your visitors recall their experience as -- Avinash Kaushik puts it best -- "I came, I puked, I left." Think of Google Analytics as the natural extension of Google Webmaster tools, two halves of the same coin; ultimately the coin you put in your pocket.

Can help answer the questions: Where do most of my organic search-referred visitors live? Aside from the page they clicked in a search engine, what other pages did they visit? How many visitors from a given keyword completed goals on my site? What's my conversion rate?

Google Trends -- Put simply, this tool provides a trended representation of the most popular topics and search queries, and helps explain the context of those terms using content segmentation (news articles, blog posts, web results, etc).

Can help answer the questions: Why did an old article I wrote months ago about Tom Brady's resilience become so popular again (if you lived under a rock)?

Google Trends for Websites -- An easy to use tool that can profile estimated traffic to almost any website (given sufficient traffic numbers) and provide visitor region, other websites trafficked by visitors, and search terms used by visitors.

Can help answer the questions: How does my website's overall traffic compare to other websites I consider competitors (or partners)? How does the distribution of visitors from different regions to my website compare to my competition?

Google Insights for Search -- A considerably better tool than Google's External Keyword Tool (mentioned above) for keyword research because it provides in-depth (annotated) trending, categorization, localization (regional interest), and more -- all in a sophisticated, interactive interface.

Can help answer the questions: What global events triggered the popularity of a given keyword? What keywords are highly seasonal and cyclical, and when should I consider targeting those queries with relevant content?

Google Instant/Google Suggest -- Some say that Google Instant will change the rules of engagement for SEO, while others say Google Suggest has been around a while, and already provides value to intelligent content creators. If Google isn't your first stop for keyword research plus competitive content ideas, it should be.