Sure. . .
There are several reasons.
IAP is a great "free" service to most of us. There is not a membership fee to access the great information available here. This is a great source to find new products, save money, and expand our knowledge. It encourages us to think outside the box. Also it is a great way to meet many new people from all over the world. The activities that occur are awesome. PITH, Castaways, challenges throughout the year. Not to mention things for Pens for Troops. The occasional fund raiser for events to help others out. One time a friend of mine was entered in a contest to try and get a commercial in the Superbowl, and the "family" on IAP helped him get through a couple rounds that he would not be able to other wise. This is an easy way for me to give back.
Sometime last year my oldest daughter entered in the youth penturners contest. She was very excited and the prizes she won were unbelievable. However the whole conflict of interest caused me to decide to go to the age group she would not be in. My father threw me out when I was 8 years old and my grandparents raised me. So I am a big supporter of people doing things with their kids, nephews/nieces, grand kids, cousins, ect. I figure this is a great skill for kids to learn and get them away from their ipods, computers. (ironic I am using a computer to write this)
And. . . It is promotion of my product, and may cause a couple people to go ahead and try it.