I glanced over the site, and was really taken by the simplicity of the approach! I've used Aki in the past, but resorted to scraping the sites I was learning from to create flash cards. This looks like it really takes the pain out of putting material in.
As a memory researcher, I'd love to see a good example of how you (or someone else) implemented readlang to learn a language. The site seems good at conveying how readlang can get flashcards cooking, but it would be interesting to hear how it was used as part of someone's language learning process (the big picture). I saw on the about page that you used it to learn Spanish, and there are a bunch of posts on the site, so it may be there and I missed it.
I'll definitely look more into it later this evening, but a few questions/thoughts I had were..
1. is there a good way to programmatically pull out flash card information (as say a JSON object)? Is the export to Anki as a csv/tsv?
2. How fleshed out is support for Chinese? What should I expect from it being in beta?
3. I was intrigued by the video player functionality, clicked the "Find something to watch now" on the features page. Clicked blindly. Arrived on a page of text in Spanish. Backed up. Realized that it was a mix of text articles and video articles. Scrolled down to a video article. Was very impressed with the player, but thought with a little less patience I may have missed it. This seems like an incredible feature (similar to fluentU's approach), and one that the link should take people to with as little friction as possible!
Sorry if any of this should have been clear from a more thorough read. I didn't have a lot of time to look, and was really impressed, so thought I would fire off my impressions before giving it a more thorough look :).