# Notes on charts

> Mark launches, sales and changes on your chart. Datacenter adds notes for new goals, campaign starts and big days, and reports include them.

Source: https://datacenter.so/docs/chart-notes
Section: Measure

A note says what happened on a day, so a jump on the chart has a reason next to it. Notes show as a small flag on the main chart. Point at the day to read them.

## Add a note

1. Open your site's dashboard.
2. Click **Add a note** under the main chart. Once the period has notes, the button reads **Notes (3)**. Or click a day on the chart: its [breakdown](https://datacenter.so/docs/dashboards#see-what-makes-a-number) opens, with **Add a note** at the foot.
3. Pick the day, write a few words, like "Launched the spring sale", and click **Add note**.

Notes are up to 140 characters. A site can have 500.

## Notes Datacenter adds

These come from data Datacenter already has. You do not need to do anything.

| Note | When |
|---|---|
| Tracking started | The day of the site's first tracked visit. Days before it show as no data, not zero |
| Datacenter's own numbers start | The day imported [history](https://datacenter.so/docs/import-history) hands over to Datacenter's own count |
| Tracking tag found on the site | Datacenter found the tag, on a site with imported history, where it takes the place of Tracking started |
| Tracking tag stopped sending | The tag went quiet (an [alert](https://datacenter.so/docs/autopilot)) |
| Goal added | You added a goal |
| Campaign started | An ad campaign's first day of spend, from connected or imported [ad spend](https://datacenter.so/docs/meta-ads-spend) |
| Big day | A day with at least twice the usual visitors |
| Unusual change | A number far from a usual day for that weekday, with its likely cause when the data shows one (see [Unusual changes](https://datacenter.so/docs/autopilot#unusual-changes)) |

## Remove a note

Click **Notes** under the chart and click the cross next to a note. Notes Datacenter added are marked **Automatic**. A note you wrote is deleted. A note Datacenter added is hidden for good.

## Where notes show

- On the main chart of the dashboard, and on [shared dashboards](https://datacenter.so/docs/client-dashboards), so clients see them too.
- In the breakdown for a day on a chart, under its number.
- In [client reports](https://datacenter.so/docs/client-reports), with a **What happened** block. The Monthly performance template has one.
- To the [Assistant](https://datacenter.so/docs/assistant), so when you ask why traffic jumped it can point to the note for that day.