Ok, so imagine the site in question is a little-known blog. I follow a link on reddit, enjoy the article, then click around to see what else the author writes.

Ok, so imagine the site in question is a little-known blog. I follow a link on reddit, enjoy the article, then click around to see what else the author writes. I find it really interesting and want to follow this author more closely. Do I then cross my fingers and hope reddit shares my taste in his other content and also hope I happen to catch it on reddit if that blog's content comes up again? No, I track the RSS and can peruse updates at my leisure without missing anything. I think it's a different model of consumption. HN/Reddit is browsing, "let's see what the chatter by the watercooler is today". RSS is "I am more than casually interested in particular content and want to be notified of updates".