How does sharing via WeekCal.com work?
Sharing via iMessage or Text using the Messages Action Menu item works by uploading your event to the WeekCal.com servers. WeekCal.com will store your event safely and generate a unique, personal web-link.
Only people you send the web-link to can view the event on WeekCal.com.
Receivers of the web-link get a small preview of the event and can tap on a button to quickly import the event into Week Calendar or any other calendar app.