I can only read/review english language sites. Across the months, every time I've checked, several spamsites have made it into the showcase (woohoo! backlinks!)
Also, I have repeatedly encountered (mislabeled by the auto discovery bot?) showcase sites marked as being english... but the site at the linked destination is clearly not english (nor multilingual).
The project's reputation would be better served by presenting 20 or so hand-picked exemplary sites. Exemplary, not with a fixation toward "number of questions" (longstanding, or providing thorough coverage of a niche topic are possible qualifiers)
As is, seems the showcase/bot mechanism is leading shady site operators to engage in tactics like: a) register domain, b) scrape, import, or just post gibberish to acheive "lots of questions, lots of apparent activity" c) achieve backlink from the showcase page and elsewhere d) attempt to sell the "now PageRanked x" domain