I have myself often pondered what I got out of blogging here. I am definitely not into publishing or media business, so that rules out most of the monetary reasons. I wondered if it was therapeutic, but, as Reginald mentions, maybe it is the Dunning-Kruger effect.
It is quite possible, even one successful project allows you a lot of misconceptions about yourselves. Admittedly, I too am in the clouds after a high score.
Ironically though, blogging is what has got me back to the ground. The moment I start feeling a bit more about myself, just going through my blogshelf reminds me of what is out there and where I am. It is not any different than watching through the Hubble Deep Field across the 78 billion light-years of universe. This is just what I have been able to see, there might be so much out there beyond my reach today. And if that is not enough, I learn a lot from reactions to what I write, and that only helps me realize how little I know.
While wishing you a Very Happy 2008, I hope that the Dunning-Kruger effect will make me blog more.