We track a lot of iCal feeds at Timetastic[0] and I thought it'd be interesting to see if we could identify when Google or Outlook's iCal feed fetchers were down or slow because the latency can vary wildly from a few hours to days.

We already log the timestamps and user agents for the feed checkins and we've got a rolling month's worth of data so this seemed like a nice little exercise I could do in the evening.

[0] Nearly 3 million per month. People like iCal a lot!

Full disclosure - I work at Timetastic, but I did make this on my own in my own time