When you configure gnus to score up the articles you read and score down those you kill, that is known as adaptive
scoring. You can also score article
s up or down yourself, by author
, or indeed any header
(I score down anything that is cross-posted to too many newsgroup
s). And you can have gnus kill any article with less than a certain score.
One feature that would be very useful if it worked properly is that entries in your scorefile can be temporary and expire automatically after a certain time. So you can effectively killfile an annoying poster for a week and then see if they've become less annoying.
But what actually seems to happen is that the date of the entry is refreshed whenever a new article from the poster appears. So unless they take a week's break from posting, they'll stay in your killfile indefinitely.