Thank you for your input. I was also thinking about implementing bookmarking feature locally. But seeing HN has its own 'favorite' feature, I decided to skip it.

This can be doable. Since HN doesn't provide an API for it, I have to parse the webpage and collect the ids for the favorited stories from there. If I get more users, I will certainly implement more features like this.

My end goal is to have maximum feature parity with the website. :)