Last night, Google Android chief Andy Rubin announced via tweet and Google+ posting that Android has surpassed 700,000 daily activations. He further clarified what he meant by activations in a later posting on Google+:

For those wondering, we count each device only once (ie, we don't count re-sold devices), and 'activations' means you go into a store, buy a device, put it on the network by subscribing to a wireless service.

700,000 is certantly an impressive number, one boosted by the recent launch of devices like the the Droid Razr, Galaxy Nexus and the rest of the Samsung Galaxy S II line. Back in December of 2010, Rubin tweeted that Android had reached a level of 300,000 daily activations.

By June of 2011, that number had reached 500,000 and that it was growing by 4.4% worldwide. Assuming he meant per month, Google has actually exceeded that previous growth rate and more than doubled in one year.

It's estimated that Apple currently activates around 450,000 devices per day, according to Flurry.