This section presents data on number of backlinks and esitmated traffic on a chart. In a glimpse, you may see how many of ranking pages have strong domains, and which ones rank thanks to the content quality.
Charts are the visualization of data that you can find under page titles in SERP:
The charts you see using Keyword Surfer are similar to the ones from SERP Analyzer. With extension you can only see two off-page factors. Surfer subscribers get access to 500+ more data points for 50 top pages in the chart view.
Charts are one of the most convenient forms that let to understand and determine the particular signals meaning. They allow to spot trends and speed up analysis.