Facebook filed for a $5 billion IPO today in what will likely be a wildly successful stock market debut.

I laughed when I recalled my post from five years ago in which I thought the idea of Facebook being worth $15 billion was crazy. That was before I got hooked on it, of course (along with about 800 million other people). Now $15 billion sounds like too little.

I’ve been astonished at the role Facebook has played in the recent revolutions around the world. It will be interesting to see how the company grows from here.