Google Calendar launched in 2006. And by "launched," of course, I mean "kind of just showed up." This was the era of Google quietly putting "beta" versions of apps on the internet and watching what people used.
People found—and used—Google Calendar.
In an era when web applications weren't common it stood out, not only because it ran entirely in a browser, but also because it was faster than popular desktop options at the time. Google Calendar was also packed with features.
An early review by Michael Arrington on TechCrunch pointed out natural language processing for events, managing multiple calendars, and Gmail integration. These are still the biggest features over a decade and a half later (though the natural language processing is now missing from the web version, for some reason).
Today Google Calendar is the most popular calendar service on the web. The app is installed by default on Android phones and shows up in Gmail's sidebar, which certainly doesn't hurt. But even without these advantages, Google Calendar offers a fast and easy-to-use calendar with great collaboration features.
Automate Google Calendar with Zapier
Want to connect Google Calendar with applications outside of Google's ecosystem? You can with Zapier, which offers Google Calendar integrations with 1,500+ apps.
For example, you could automatically create Trello cards using Google Calendar events, or add events to Todoist (or tasks to your calendar).
Create new Trello cards from new Google Calendar events
Add new Google Calendar events to Todoist as tasks
You could also use Zapier to automatically add appointments from Outlook to Google Calendar, or vice-versa.
Add Microsoft Outlook events from new Google Calendar events
These are just a few examples. You can build any integration that you want. Click here to get started.