0: If it meets the guidelines, this might make a good "Show HN" because Show HN is for feedback on implementations submitted by the person who built them. Show HN guidelines:
https://news.ycombinator.com/showhn.html1. Amazing progress since the last time we talked about ReadBoard. Congratulations.
2a. Having to pick five topics to try out the site is a distraction. I just want to see how it works.
2b. There appears to be a topic for every possible tag. There are far too many for a new user to parse.
2c. The tags are someone else's not mine, and therefore the tagging is editorial. But the editorial work does not create a hierarchy of importance. India, Startups, Philosophy, etc. are all given equal weight even though surely some have better content than others.
2d. My suggestion is to narrow down the number of topics and focus on providing excellent content for a few...or in the extreme eliminate topics and just focus on good content. Either way this means deciding who the target users are and are not.
3a. The user interface of cards takes up a lot of screen space. For me, it does not provide enough stories per screen to easily decide what is or isn't good. Or rather, because there are so few stories and I am selective, there is a high probability for a screen to contain nothing I am interested in. So my choice is to dig deeper or navigate away from the site. Not seeing anything interesting makes navigating away more attractive and digging deeper less attractive.
3b. My advice: make it as easy as possible for the user to find something interesting because marginal quality content consuming significant screen space makes work for the user. If I want that, I can go to Facebook.
4. Reproducing the content from other sites on ReadBoard did not add value for me because: there was latency while the site was loaded and it the text was still surrounded by web widgets rather than standing alone. My advice: look at Firefox's Reader Mode [and consider talking to an attorney about copyright and looking into Google's definition of content farming].
5. The Chrome extension is not a bad place to start app development.
6. I'm not sure I want to share all my contacts.
7. The guest experience was mediocre, since I could not try out the discussion feature, and that's the core of the site. My advice is to allow commenting without registration during the "Feedback" periods. Maybe a unique URL that logs people into temporary accounts automatically when the "guest" link is clicked might work.
8. ReadBoard looks like the result of significant effort. My comments 3, 6, and 7 all hit on what I see as the biggest challenge: focusing on the interests of the user over those of ReadBoard as a business.
9. Comment 5 indicates a way in which the interests of ReadBoard as a business and the interests of [some] potential users align to mutual benefit. Finding more such alignments is hard because it requires change, but the easier path is by changing ReadBoard toward the user's interests.
Good luck.