Let me begin by saying, I do understand this is a business and the site owners need to recover their costs.
But, I had the impression that it could be used for free, and one only needed to upgrade to "Premium" (or better) to get additional features.
However, now that I have "lingqued" 20 words, it appears that the site is essentially unusable. I can't even mark the words I already know. When I click on one to do so, I just get the upsale panel on the right instead of the one that lets me mark it as known.
So, I guess I can still listen to and read the lessons, which is cool, but I can't actually make use of the known-words list (and highlighting of words I don't know) without upgrading. Is that right? Or is there some other way to do it that I'm missing?