I never stopped using RSS. I follow a few hundred blogs (many of them have only very very few posts. Rule of thumb: The lower the post frequency, the higher the quality). I host my tinyRSS. I consider offering it to the public for free.

Here is a good RSS feed for Hackernews: http://hnrss.org/newest?points=300

Here is a service to convert a twitter feed to RSS (never really understood twitter, sorry) Example http://twitrss.me/twitter_user_to_rss/?user=Lsigurd

Here is a service to convert many RSSless websites to an RSS feed. Works soso. https://feedity.com/

EDIT: Hackernews RSS feed link was wrong