Google Calendar

I changed my primary mailbox from Hotmail to Gmail some days ago. Also the Geocaching.com . Today when I clicked the mail of geocaching, a notice above the Sponsored Links asked me if I log this event to my Google Canlendar.

I follow the instruction to do so, and created a "geocaching" canlendar tag for these staffs . I'm planning to share or log this canlendar with someone be interested in Geocaching job. Tell me if you are the one. :P

But I have no idea how the Gmail judge a mail wether make sense with masking to calendar.

Keep observing.