A user reported that the iCal feed provided by the OSSG blog caused Google Calendar to repeatedly send event reminders for old events. After some digging I am still not sure why Google Calendar behaves in this way; I think the timestamps on the feed items may change under some circumstances, making Google Calendar think the events are “new” and thus send and email.
In an attempt to resolve this issue I have upgraded the software that provides the iCal feed and restricted the posts shown by default in the feed to those after a date 1 month in the past. Hopefully the software upgrade will prevent the issue occurring in the future, if you still experience problems please let me know. I’ve subscribed my own Google Calendar to the OSSG feed now, so I shall share the pain if there is an issue
I’ve also changed the default feed type on the blog from the venerable vCal type to iCal and introduced a CAPTCHA and confirmation step for user registrations. This will hopefully reduce the incidence of spam-bot registration.