Yep, normal Usenet application response when someone REplies.
Using http://groups.google.com/advanced_group_search we see lots of authors
named Aardvark had made posts.
Results 1 - 10 of about 28,400 for author:Aardvark
Well a quick advanced_group_search does not show "Kernel Black Flag"
for me so I'll assume Kernel Flag has marked his posts to not be archived.