Thousands of sites need a calendar component and would far rather rent one than build it. That’s a subscription business with unusually low churn, because once a calendar is embedded and populated nobody wants to migrate it. Event calendar is the phrase for a product almost every organisation needs and most implement badly. Venues, cities, universities, associations and communities all maintain one. The name suits a calendar product, an embeddable widget, a listings platform, a local events site, or an API serving event data.