The Wall Street Journal posed the question of whether Facebook is worth $100 billion. I still have no idea, but I continue to think Facebook is now facing a very formidable competitor. My initial reaction has strengthened. G+ circles are a big deal and clearly the differentiator. As for growth, technowizard Leon Haland has shared some interesting data that shows the relative growth rates of Google, Facebook and Twitter. Haland said that Twitter got 10 million users in 780 days (2.13 years), Facebook got 10 million users in 852 days (2.33 years), and Google Plus gained 10 million users in just 16 days (2 weeks). Google Plus is growing exponentially. The Christian Post reported on Wednesday that Google Plus had reached 18 million users. Regardless of the exact numbers, I see G+ growing very rapidly becuase it has a better privacy model than anyone else, as far as I can see. With Facebook, a friend is someone for whom you have accepted an invitation. Are they really all your friends? How many friends can a person have? What is a friend? With Google+, you can establish circles for best friends, semi-friends, acquaintances, people you can’t stand, favorite people, geniuses, half-loaves, golf buddies, political cohort, heard of them, never heard of them, etc. In other words, you define your circles, you put people in one or more of the circles you create, you easily upgrade or downgrade which circle a person is in, and you are confident that none of your “friends” can see which circle you have put them in. As that notion takes hold, I think millions of people will migrate to Google+. I currently have 169 people in my circles and there are 117 that have me in their circles. The magic is that they don’t know what circle I have them in and I don’t what circle my “friends” have me in. I may be in the “jerks” circle of them all, and I may have placed many of my connections in the “heard of them once” circle. I have seen G+ connections come in to me that show that someone has 7,000 people in their circles. That is ok with me. Someone can have 100 million people in their circle if they want. I see Bill Gates, Larry Page, and Sergey Brin in some people’s circles. Are they really friends of these czars? Maybe. I doubt it. My rule of thumb for “friends” is as described previously. My criteria for “industry friend” is someone I have actually met and talked to. Someone else may have a criteria of “heard of them”. It doesn’t matter. The key thing is that if you want to post a message to your family circle or best friends, you know that only this limited group of people that you have defined will be able to read your post. The point is that G+ gives you control. You define what a friend is. You can allow large numbers of people into your circles if you choose, but that does not mean that they can read your posts to “soccer moms” or “my political cohort”. It is going to be interesting to see how the exponential growth of G+ plays out. Maybe everybody will be connected to everybody, but at least you will have the ability to share with everybody or just your “motorcycle friends” or whatever. Stay tuned.