I'm a big fan of DuoLingo and Tiny Cards. I use them all the time and with great enthusiasm. But Tiny Cards (German, Italian, French, and Spanish) is strewn with errors and weirdness. And the error-report feature seems to have no effect. I understand (barely) that Tiny Cards has a one-to-one algorithm vis-a-vis DuoLingo's more tolerant and sensible model. But I DON'T understand why they can't fix the errors. What's the point of having an error-reporting process in place if you don't fix the errors? I haven't kept a log - I guess I should start doing that. But one that recently happened was "come" in the Spanish kit. EVERY other singular verb reverts to the masculine "he drinks", "he writes", etc. (Really? Women don't drink or write?) This one marks me wrong and says "eats". I've marked the card as an error for months. Love DuoLingo. Like Tinycards. Tinycards needs a better feedback mechanism.
Tiny Cards is (mostly) user-generated - except for decks that are labeled "Duolingo" (?). You put yourself in the hands of your peers when you use it. The decks could be made by a 40-year-old linguistics expert, a native speaker, or an 8-year-old kid with enthusiasm but indifferent grasp of grammar.
I do note one way to report errors, and that is to use the "cards" rather than "lessons" tab at the top of a deck, and use the pull down menu at upper right to report a problem. It is unfortunate that there is no more immediately obvious way to report errors. And note also, because many decks are not in any way "official," and because the report button offers no way to explain your criticism there is no guarantee that if you report an error the maker will act to remedy it.
In theory the most favourited decks should be the ones with less or no errors... people use them for a reason... even though I've made one deck to try it out with (hopefully) no errors and I am the only one who favourited it. :)
But yes, there's a lot of junk on TinyCards.. there should be a better quality control there.
You could always make your own TinyCard decks. If a TinyCard deck you found is missing a few words, for example, add those words to your own decks. Or even better, if you have time, copy all the cards from the downloaded deck to yours, then make your additions from there and un-favorite the downloaded deck.
Reporting problems will go directly to the makers of those decks, so you don't know if they are still active and/or motivated to fix those problems, unfortunately. If Duolingo didn't make a deck, they are not responsible to fix it.
Done. Did you get anything for this? https://tinycards.duolingo.com/decks/24a12a39-55ae-49bc-a484-ada9b43fdcfd