Well that is a hard question to answer. We each have their own reason. For me, when I first got an internet connection (just about when it became a commercial venture) I had been getting help protecting myself from various people on BBS's and Newsgroups (BBS's are basically pre internet if you didn't know) and they expected nothing in return except a kind word. The only way I could every repay them is to help others as I was. Also I have a problem with both shoulders that keeps me from working, helping people keeps me busy and keeps my mind occupied.