April 1st also happens to be the start of Q2. I think it's kind of nifty that Google is unwilling to let a non-vacation holiday only celebrated by a handful of countries (http://en.wikipedia.org/wiki/April_Fools'_Day) disrupt its product planning.

(It's also shrewd business, if its competitors have "Start of Q2" stuff they'd like to announce that they put off until April 2nd).