There's a lesson there for people who want to phrase their startup idea as "X for Y". You should ask how similar Y is to the userbase that originally made X popular, and whether you are capturing the qualities they have in common or just randomly cargo-culting a successful product. "Flickr for video" works because a photo-viewing community and video-viewing community are substantially similar: they both have similar casual interactions around shared multimedia, and they both benefit heavily from recommendations, discovery mechanisms, and social sharing. Similarly, "Google for China" works because people in China have information needs too yet actual Google has an antagonistic relationship with the CCP. "Uber for laundry" and "Uber for housecleaning" are both terrible ideas because Uber's value proposition is that you can get transportation on-demand and it can be done by unskilled people as long as they get you safely to your final destination, while both housecleaning and laundry are stuff you do once a week, on a planned basis, and you really want to trust the people who are doing it. "Uber for grocery delivery" (Instacart/UberEats/DoorDash/Postmates) is a decent idea, though, because grocery delivery is also something you want on-demand, do regularly, and can be done by basically anyone.