The Apple Store is back up

The yellow Post-it is usually a sign that something new is coming

[UPDATE: The store came back up shortly after 6:00 a.m. EST Sunday. If there were any changes, I can't see them.]

Sometimes Apple (AAPL) takes its online store off-line for cosmetic changes -- like maybe a Father's Day sale. Sometimes it's to clear the decks for a new piece of hardware. What that might be, we can only guess. Among the products due for an upgrade:

• Airport Extreme and Time Capsule. Supplies have been running short and last week's update to the OS X Airport Utility made references to next-generation models.
• MacBook Air. Last refreshed in Oct. 2010, a new version of Apple's lightweight laptop is widely rumored to be in the works. According to Deutsche Bank's Chris Whitmore, however, Apple is holding it for the release of OS X Lion, due in July.
• Cinema Display and Mac Pro. Not much chatter about either of these, but their last refresh was July 27, 2010.