Ended up starting a simple project over the week with that in mind [1], but wanted to discuss with others here too.
Spam reviews: With moderation and anti-spamming tools, it seems to have “worked” for rating products (Amazon), offline businesses (Yelp), and others so why not online services (websites)? The 5 star rating system measures “satisfaction” somewhat well, but the “popularity” part (number of stars) is easier to spam. I really liked the format used in [2], so I used a modified version of that in my project. I feel the “never heard of it” option could suppress spams.
Apathy: What would motivate folks to start contributing? It should probably be dead simple so I thought a browser extension could work well, both for the people leaving and consuming reviews. This obviously has its limitations on mobile. The real motivation probably comes from the fact that the review was helpful to somebody. People seem to go nuts on reddit gold, so I guess that’s validation if any, so I tried to add something like that.
Privacy: Related, but some people don’t like leaving traces behind on the web. I feel the best way is to be transparent as to what is happening and give them as much control as possible. For example, make it easy to view and remove everything they know about the user. Still probably won’t satisfy everyone.
There are other smaller issues that I can think of (e.g. not all websites fall into a "rate-able service" category), but probably missing some big ones too. Please feel free to share what you think.
[1] https://chrome.google.com/webstore/detail/lome/necafokehnnolgnjmapmlmhigjmlelpl
[2] https://2018.stateofjs.com/front-end-frameworks/overview/