Blogs and websites that generate lots of content are akin to News. You don't subscribe to them, and have HN to let you know of something important happens.
RSS is for the long tail of blogs that don't post very frequently, but when they do, its worth your while.
The ideal entry in my RSS feed is one that has new addition once per week or less. This way, I can follow a very wide array of people without getting overwhelmed, nor having to miss if their post don't make it to HN front.