"I just find it curious that these specific themes tend to occur again and again." The markets for each of these categories is huge with plenty of room for inn

"I just find it curious that these specific themes tend to occur again and again." The markets for each of these categories is huge with plenty of room for innovation in specialized niches. It makes sense to me to see plenty of competition in each category. That said, they do tend to line up pretty well with the demographic involved in your typical internet startup: Project Management/Bug Tracking = Developer Discussion Forums = Gamer Music/Events = Hipster Dating and Match-Making = Single And there you have your computer programmer with ironic t-shirt, no girlfriend and a level 70 mage in WoW.