[enraged_camel]

Equally suspicious are popular but controversial stories that disappear off the front-page within a very short amount of time despite having accumulated lots of votes and comments quickly. I've always gotten the feeling that there are groups of users who flag submissions to make them disappear.

[notlisted]

Exactly, though I suspect moderator intervention, not user groups. Notably, anything remotely critical of AirBnB. Changes are too sudden (e.g. story on #3 position, loads of upvotes and comments, and while I'm formulating a comment, it disappears and a completely inane and inactive post takes its place). At times I've even had trouble finding the original post again in the first few pages. Maybe Porter could shed some light on that too.