This is the number of free trial subscriptions that begin in any period of time. Together with your trial conversion rate, this metric is a key growth indicator.
Measurement: The number of free trial subscriptions started in the time period selected.
The free trial chart will always show you the number of trials started within each of the sub-periods visualized. For example, if you view the last 6 months as your overall time period with each bar in the chart representing an individual month, the individual bar will only display the trials that were started in that month.
Free trials signup rates are a very important metric to analyze in the context of (1) your seasonal trends and (2) your customer acquisition spend. Seasonal spikes in trial signup rates are an indicator that other acquisition channels such as winback campaigns should also be intensified.
Related to this is the need to consider the effectiveness of your marketing efforts from a signup rate perspective. ROI should be examined in terms of what each individual new free trial is costing, and how this changes over time.