Ask PG: Do comments from new users get auto-killed too easily?

Some comments that definitely aren't spam earn the status of 'dead.' For example:

http://news.ycombinator.com/item?id=1567347

http://news.ycombinator.com/item?id=1566744

Those posts seem to have two things in common:

* they are both from new users with low karma

* they both contain links.

Is there an auto spam-killing function on a rampage? :-)