They take it down during WWDC keynotes and other major announcements, yes. But there are other instances where the store will go down outside of those periods.

They take it down during WWDC keynotes and other major announcements, yes. But there are other instances where the store will go down outside of those periods. Sometimes it's for maintenance, but more often than not a new or updated product appears (e.g. a product line gets a speed bump across the board).