1. Reddit is the monopoly in online newsboards. As long as it is there, nothing else can prop up and gain traction. However, I cannot exercise my right to free speech on the website without risking getting blocked by a moderator or even admins. Net neutrality should force reddit to carry my opinions and preserve my comments as I typed them. Also, they shouldn't be allowed to display ads. That results in a "fast lane" for people who pay them.
2. Facebook is the monopoly in social networks. As long as facebook exists, nobody can become relevant. Sure there is stuff like instagram and snapchat, but my Facebook profile is my de facto online phone number. Facebook should not be allowed to block my profile, flag my posts. They must carry my posts and content like anybody else's. Again, no ads can be allowed in a neutral net.
3. Youtube is the monopoly in user created video. They should not be able to block my account or pay me less money if their advertisers don't like my content. All content must be treated equally. Everyone should get access.
All of these areas are natural monopolies, just like last mile broadband/fiber. At any time, there can only be one "Youtube". It can be replaced by something else, but there will always be one highly dominant video website, which people will inevitably visit to see the latest movie trailer or music video. Why does net neutrality exclude all these?