This is an interesting question. In my experience, Tripadvisor used to be 'the review' place. It seemed impossible to overtake them, since a review aggregator n

This is an interesting question. In my experience, Tripadvisor used to be 'the review' place. It seemed impossible to overtake them, since a review aggregator needs some critical mass of reviews to even get started. However, in the last few years, I have found Google Maps more useful for reviews - looks like the critical mass has shifted. They were able to take advantage of the fact that it is easy and natural to check out the reviews of a place while looking it up on the map. Now, however, I worry that Google will try to monetize the maps more and more in ways that are hostile to the user. They have already started showing ad-sponsored restaurants/locations on the maps, last I checked. Reviews are so critical to many businesses (particularly restaurants), it seems important for maps and reviews to be run by a user-friendly entity, ideally something like OSM. Providing such a service is expensive, however. The fact that OSM does not have a decent Android app even is telling (Osmand is laggy and barely usable; Organic maps is nice, but is not a replacement for Google maps). So we are stuck in the situation we are in, and I am not sure what a good solution would be.