When did the format on the join date change? The new numeric system sort of looks like the birth and death dates on a biography, and it appears as if we all died young.
Edit: Check that. It appears I died before I was born. Bummer. Never had a chance.
Oh I'm quite aware that the rest of the world does it wrong differently. I just found it amusing when my brain didn't process it properly and was wondering when it had changed. Having month, date, and year in there does make it look less like an epitaph, though.
My assumption is that the year is just tacked on to the logical "general to specific" of month-day when needed. Month-day makes sense on its own, so why bother reorganizing it all when the year is added. That's my justification for the commas around the year in full form as well.