UPDATE: How disappointing. It turns out that Apple was just doing some maintenance? Polishing a few iPhone screens maybe?
We've studied the store and we can't find anything new, apart from a Mother's Day special for the UK (Mother's Day happens at different times around the world, so we don't think that is the reason the store was down elsewhere).
However, the details below may still help you make your predictions about what Apple might do next.
Normally when Apple takes the Apple Store offline its because it is about to launch a new product.
Here are our odds on what might be in the pipeline.
New Mac mini - last updated in October. [No]
MacBook Pro with Retina Display - only just updated [No]
MacBook Air - last updated in June 2012... How about a boost and a lower price? [Maybe]
iMac - last updated in October, but still not really meeting demand so an unlikely update [No]
Mac Pro - well Apple has to remove it from sale in Europe on 1 March, which is Friday, but it's already updated the store to reflect this change. [No]
iPad mini - expected update this summer [No]
iPad - update expected later this year [No]
iPhone - later this year [No]
Thunderbolt display - we're sure an update to Apple's display would sit alongside a major product refresh [Maybe]
Apple TV - the set-top box only just had a firmware update, plus we're sure Apple won't slip another update under the radar [No]
Time Capsule/Airport Extreme - it's feasible that Apple could bump it up to 802.11AC [Maybe]
iLife for Mac - about time... It's getting embarrassing [Maybe]
iWork for Mac - Apple should be very embarrased about the lack of updates here. They should react to Microsoft's recent Office for Windows update and Office 360 and sort it out. [Maybe]
We don't think that they would take the store down for any other reason... But we might be wrong.
And of course it could just be maintenance...