I suggest a separate forum with ONLY Google update threads (you know, the marathon ones). Nothing else should be discussed in that new forum.
Collect all the current ones and all the past ones there: all those threads should be removed from the Google SEO forum.
I also suggest that those update threads do not get featured in the "recent posts" list.
Oh, and a post in that new forum should not count in the total post count for a member posting there.