The Cohort Orders per month metrics tells you the number of orders placed.
1st month - orders placed the first month
2nd month - orders place the second month
This is non cumulative metric
If you are curious to see the number of Returning Orders per month by cohort. All you have to do is subtract the amount of orders from the 1st month by the size of the cohort, and you will see the amount of returning orders for the first month. The following months are returning orders by definition, so you do not need to do anything. You can download the data into a CSV by clicking the download button on the upper right side of the chart.
You can look at this to understand the amount of orders a cohort is making.
If you do a campaign on a specific cohort month - Black Friday. You can make a campaign 3 months later for that group of people, you can see if it makes an impact with orders over time or at the timing of those campaigns.
When you segment by product, it is product by the first order. It is looking at all the customers who made their first order with that product and what their order history is there after. For example, my first order with the company was Product A, so when I segment by Product A I am apart of that order count, but my subsequent purchases might be Product B, Product C, but it still counts those. The segmentation only looks at what your first order. So this is an interesting way to see if there is a favored first product that causes the best repurchase and order counts for your customers.
Coming soon - A metric to show what your customers are buying in their subsequent orders.