I'll give it 5 stars, because I think it's a neat idea, a good use for the wiki and a solid implementation, but there are some improvements that can be made. Most importantly: information is sometimes incomplete. For example, I went on Pinterest and it gave me the anti-consumer card, but there was just a general description of the company and nothing else, so it made an impression that Pinterest isn't doing anything shady, but in fact, if you go on the consumer rights wiki page for Pinterest there are multiple incidents, which aren't present in the card I got. Second, some color coding would go a long way to draw attention to things that are really bad and you should really know about, instead of just having them all in a list that a person may or may not read through. Maybe the background color for individual incidents should be different from each other, drawing attention to the really bad ones, or maybe the whole card should be a different color if a company is doing a lot of anti consumer stuff. I also think the general description of a company is unnecessary and takes up way too much space in the card. I think it should be collapsed by default and if someone happened to not know what this or that company is, they can expand it.

Edit: As I'm using it more, there are more things that are questionable about the implementation. First, it seem to just look through the text on the page and match words, because I got "Shell", the company, on pages that have nothing to do with it. And there are more examples where that came from. That's not good. Second, on some sites (for example Steam), it just blasts me with 10-15 cards, a lot of which aren't directly relevant to the page I'm on, but I guess it caught something in some text, and then I need to go through these 15 cards one by one, and I know that "hide for this site" option is there, but I think it's just not a good idea to have 10 cards in a row in any scenario, because even I, a consumer rights conscious person, start glazing over it after 3 or 4, and just skipping. That's not what you want to train people to do. Ideally there should be just one, the most relevant one, at most 2 cards, but after that it starts to feel less and less like I'm being helped to stay informed and more and more like a test of patience.