As Michelle says time is the main factor. I haven't any comment of you in my photos, you'll understand that I prefer to apply my time to the people who like my images because is more probable that I like the photos of the people who like mine. As Tom, I don't have time, but I try to have time for the people who have time for me. Renderosity is a community, this means relationship and I feel really well when I encourage people who encourage me, you know, not divinities, this isn't The National Geographic, only friends sharing their images, their time, their opinions and perhaps something more.