Oh yeah, definitely not a scam. My beef with it though is that it's not curated from the top very well. I wish there were more options and better ways of divvying up content. It would be neat to be able to filter stuff out based on region, language, topic, and I'm sure many other ways I haven't yet thought of. I almost wish there was no central page of popular posts, but many central pages based on these filters. Or like a map you could click through to find your region, for region-labelled posts. Or, or, or... but I'm sure it's all coming.

And the Ponzi scheme argument is true but holds no weight because, well, this is how currency and reputation operate by definition.