It depends on what you mean by "here". If you mean forums, then there are many reasons for many people. My personal reason is because I was reading comments on the charlie thread and checking this one for great answers and to answer a question such as this. In short: because forums interests me somehow You question could also be taken as "why are we on earth or in existence?" To which I reply with my own answer which is because of random chance, which, from the perspective of billions of years ago, had a very small chance of happening.
I don't know what any of that meant so obviously you are the true philosopher on this thread. I believe you beat the game