Ask HN: How do Hacker News articles become “Dead”?

[SirDudeness]

I'm using the public BigQuery Hacker News data to track popular keywords and I'm thinking that filtering out "dead" articles would be helpful, but I want to understand how articles become "dead" first. Does anyone know what the process is?

[tlb]

The submitter can delete it, or several users can flag it.

[SirDudeness → tlb]

Thanks!