# Segments and best send time

> Group customers by source, spend and activity, send groups to Klaviyo, Mailchimp or Attentive, and reach each person at the hour they are most likely to act.

Source: https://datacenter.so/docs/segments-and-best-send-time
Section: Measure

Two things Datacenter knows that your email and text tools do not: where each customer came from, and when they tend to act. Segments and the best send time put that to work.

Both are on paid plans: Solo, Studio, Agency and Custom, with [customer profiles](https://datacenter.so/docs/customer-profiles) filling in.

## Segments

A segment is a saved group of customers. Open your site's **Profiles** tab, then **Segments**, then **New segment**.

Pick any of these. A customer has to match all of the ones you pick:

| Rule | Matches |
|---|---|
| First source | Where they first came from, like `instagram` |
| Last source | Where they came from most recently |
| Ad platform, campaign, short link | On the first or the last touch (under **More options**) |
| Orders, at least | People with this many orders or more |
| Lifetime value from, to | People who spent in this range |
| Last seen | Seen in the last 7, 30, 90, 180 or 365 days |
| Email and texts | Opened or clicked an email, clicked a text, or either, in the last 90 days |

**Count people** shows how many match before you save. After saving, **See them** opens the customer list filtered to the segment, and **Export CSV** there downloads it.

A site can have up to 50 segments.

### Send a segment to your email or text tool

Under **Send to**, tick any connected [Klaviyo](https://datacenter.so/docs/klaviyo-connector), [Mailchimp](https://datacenter.so/docs/mailchimp-connector) or [Attentive](https://datacenter.so/docs/attentive-connector). Then:

| Tool | The segment becomes |
|---|---|
| Klaviyo | A list named `Datacenter: ` and the segment name |
| Mailchimp | A tag with that name on each member |
| Attentive | A segment with that name |

Every 15 minutes, Datacenter adds people who now match and removes people who stopped matching.

- Only people the tool already has are sent. Datacenter never adds new contacts to a tool and never changes anyone's consent.
- Attentive is updated by email, so it needs **Show contact details** on.
- Unticking a tool, or deleting the segment, stops the updates. The list, tag or segment stays in the tool.

## Best send time

Each customer page has a **Best time to send** card: the hour and day that person is most likely to act, and the time zone it is in.

### How it is worked out

Every time a customer does something, Datacenter adds a weight to that hour of their week:

| What they did | Weight |
|---|---|
| An order | 4 |
| A click (email, text or short link) | 3 |
| A visit or an event | 2 |
| An email open | 1 |
| An email or text sent to them | 0 |

Opens count little because many mail apps open mail on their own. Sends count nothing: they say when you mailed, not when the person was around.

Then:

1. The week is moved into the customer's time zone, from their Klaviyo profile when it has one, else your site's time zone.
2. Each hour is smoothed with the hours next to it, so 6:55 and 7:05 count together.
3. The busiest hour of the day is the best send hour. The busiest day is the best day.

**Customers with little history** (less than about two clicks' worth) get your site's pattern instead: everyone's weeks added up, each person counted once, so a few busy customers do not decide for all. The card says when it uses the site's pattern.

Times move by whole hours at today's offset from UTC. A time zone with a half hour, or a visit from before a daylight saving change, can be an hour off.

### Best hours on the Profiles tab

The **Best hours to send** card shows the site's pattern by hour of the day, with the best hour and day.

Your site's time zone is the one most of your customers have, or UTC when none is known. To set it, open **Times in ...** under the chart, pick yours and save.

### What your tools get

Each connected tool gets `datacenter_best_send_hour` (0 to 23) and `datacenter_timezone` (Mailchimp: `STBESTHR` and `STTZ`) on each person. Build segments in the tool on them, such as people whose best hour is between 6 PM and 9 PM, and send each group at its hour.