This chart shows the growth of unique logged-in VizHub users from its August 2018 launch through March 2022. A black line chart traces the cumulative user count over time, with annotated milestones like the VizHub 1.0 release, a Kickstarter for 2.0, and the Datavis 2020 launch. The code uses D3 v4’s `d3.line`, `d3.scaleTime`, and `d3.scaleLinear` to render SVG paths and circles, while `d3-svg-annotation` adds callout labels for key events. Data comes from a CSV file of date and user totals.