Google opened their I/O Developer Conference today. In the keynote they called out a bunch of statistics at their I/O Developer Conference today – “900 million activations to date”, “1 million+” activations per day.

First, that ‘plus sign’ bothers me. Any time companies move from specific to vague, directional vague ness it’s worth noticing. Sometimes they do it because they have reached some point where it doesn’t really matter so much. Is it 1.5 or 1.3 million? In the grand scheme of things, that difference does not matter much. This is probably what is happening at Android. Eric Schmidt was quoted last month as saying 1.5 million per day. A month before that it was 1.4 million per day. By our math, they are now activating close to 1.7 million phones today.

Google reported 900 million activations to date for Android. That is a big number, and makes a good headline. After all, they reached 500 million only last September. The notion of activations has never sat well with me. It is not that useful to people who care about such things because it says nothing about the market today. If you are a developer, you do not care that Android has this many activations, you care how many people are using Android phones today. And that is a very different number. If you buy a phone and turn it on, that is one activation. Two years later, you get a new phone and a new contract, you turn that on and you have a second activation. But chances are you throw that phone away. (Or if you are a particularly obsessed analyst you put on your phone museum shelf in between the Startac and the Palm Pre.) Android’s activation number does not count churn and upgrades. If you factor in actual usage, the installed base for Android is closer to 550 million. Still a big number, but half the audience size for an app.

We track Google’s Android numbers, and the numbers today match pretty neatly with our figures. We have them reaching 902 million cumulative activations by the end of May. So they are adding 1.76 million devices a day. By the end of the year, they be above 1.3 billion total activations, or an installed base of 800 million.

Where is that growth coming from? By our math, about 700 million Android phones will ship this year. The US, Europe and Japan combined probably account for about 400 million of those. That leaves 300 million from the rest of the world. This should make it clear how important the emerging markets are to Android growth. A separate question is how much of this will come from tablets. Our best guess is that about 100 million of those Android activations will be tablets, and this is largely an emerging markets phenomenon.