One reason I upload is so I have stuff stored somewhere, because I like to clean out my computer once in a while so keeping stuff would be a pain in the backside. Another reason is because I enjoy as other people have confessed, to get comments and in my case also favorites, makes me feel like I reached out the vision I had in my art appropriately and it is a great honor. Leads to me taking stuff personally at times though. Finally it is also for commissions, for hoping that someone would like to buy an art piece from me.