I thought this was weird too, because both YouTube and reddit are quite addictive, just like Facebook. YouTube's recommendations are an endless pit of wasted time unless one takes care to view only a small, curated set of channels with daily time limits. As for reddit, it's quite noisy (like Twitter) and attracts a lot of what I consider low value comments and posts (the kinds that are discouraged on HN and get ruthlessly downvoted to oblivion here).