Customer Acquisition Cost (CAC) is the cost a business incurs to acquire a new customer. This includes the fully loaded costs associated with sales and marketing to attract a potential customer and to convince them to purchase, divided across all new customers.

DAU/MAU Ratio (Daily Active Users to Monthly Active Users ratio) measures how active monthly users are on a daily basis. In other words, this engagement metric measures the number of days in each month that users performed an activity that qualifies them as active users. A higher DAU/MAU Ratio generally indicates high stickiness, meaning users consistently return to the app.

Email Bounce Rate is the percentage of emails that have not successfully reached recipients. An email bounce occurs when a sender receives a Non-Delivery Report (NDR) for an email. The number of email bounces divided by the total number of emails sent gives the Email Bounce Rate.

Email Click Rate is the number of unique recipients who clicked on any link in your email, represented as a percentage of successfully delivered emails. This metric is a good indicator of how click-worthy your subject lines are, and can also be used to gauge email deliverability.

Email Unsubscribe Rate is the percentage of email addresses that unsubscribe from an email marketing campaign, out of all email addresses that successfully received an email. Email recipients can choose to opt-out of mailing lists and this action is called an unsubscribe. Regulating the frequency, content, and purpose of sending emails can reduce Email Unsubscribe Rate.

Email Unsubscribes is the count of how many users unsubscribe from your email distributions over a defined time period. It helps your understand the health of your email distribution list and the effectiveness of your email communications.

Emails Bounced is the count of emails that were not successfully delivered. Specifically, it's the count of Non-Delivery Receipts from your recipients' email servers.

Emails Opened is the number of unique recipients who opened your email. Because the number of people who open your email impacts every other downstream metric, such as clicks, it makes sense to pay special attention to this one.

Full Resolution Time is the time duration between the ticket creation date and the ticket solved or closed date. Along with a solution that helps the customer and solves the problem, the less time it takes to get to a resolution is good for you and good for the customer. Resolution time is usually measured in hours or days.

Full-Time Employees generally work more than 4 days or 30 hours a week and are permanently employed, as opposed to being temporary or seasonal. In many countries, a Full-Time Employee is also entitled to health-care benefits and vacation pay among other legal employment standards.

A company's Gross Burn is the total cash spent on operations. These costs typically include all salaries, rent, and other overhead as well as interest and taxes. This metric is often confused with Net Burn, which is a measure of negative cash flow, and includes revenue and expenses.

Gross Monthly Recurring Revenue Churn Rate (Gross MRR Churn Rate) is the percentage of recurring revenue lost due to both cancellation and downgrades. Note that it is common to express this metric as a monthly rate, though it can also be expressed as Gross ARR Churn Rate.