Yep, calendar spam has gone mainstream. Although the practice isn't new, it seems more spammers are taking advantage of Google Calendar's default settings.
Under "Event Settings," there's a feature which allows anyone to insert advertisement-like invitations to your regularly scheduled programming just by sending you email. Even if you haven't responded to these invitations, the phony event's information could appear between your dentist appointments and due dates.
Users have reported promises of free iPhones and instant weight loss popping up in their calendars. The event information for these invites contain web links, which might lead to websites ready to steal your Social Security number or credit-card numbers.
You might want to consider turning off the automatic invitation feature in your Google Calendar, even if you share it with family, friends or colleagues. You'll still be able to keep your mutual events organized — all parties will just need to respond to the invitations before they're added to the calendar.
Here’s how to stop your calendar from adding spam calendar invites.
How to stop Google Calendar from adding spam invitations and events
Step 1: Go to your Google Calendar and click the gear icon near the top right.
Step 2: Select "Settings" from the drop-down menu.
Step 3: Choose "Event settings" from the left side navigation bar.
Step 4: Click the drop down arrow next to "Automatically add invitations."
Step 5: Select the last option, "No, only show invitations to which I have responded" from the drop-down menu.
Your calendar spam frustrations should now be relieved.