This line chart displays the annual number of Facebook users from 2008 to 2017. It uses D3 v5’s `scaleTime`, `scaleLinear`, `axisBottom`, `axisLeft`, and `line` to render an SVG with labeled axes and a red, bold stroke. The data is loaded via `d3.csv` from a GitHub gist, with year values parsed into Date objects and user counts converted to numbers. The chart includes a title, axis labels, and grid lines styled via CSS.