I wrote this community visualization because I wanted to be able to see annotations directly on time series charts.
It uses D3 and the wonderful d3-annotation package. It also uses the dscc package for tooling and the various examples at the community viz repo got me started.
The visualization includes various ways to style the chart and also supports filters when you click on an annotation.
In order to associate annotations with the chart you'll want to have a data source that has a date, metric and annotation column, for example this sheet.
The real power is when you blend your annotations data source with another source, eg Google Analytics. All you have to do is use Date as the join key.
The published version of this visualization is deployed at:
gs://analytics_buddy_viz/timeseries
An example of the visualization can be seen here.
This code was written by Michael Whitaker.