Got this from a discussion on Netiquettes on the TLUG mailing list. It should visualize Thread Hijacking for you if you’re used to broken mail clients that don’t support threading:
With the percentage of clueless people, who have no regard for Netiquette, growing so fast, the battle is starting to look like a lost cause. I’d really hate to see the Internet turn into a wild wild net or the other extreme; a closed system only available to the clued.
Again, I’m posting these links to articles that everyone should read at least once in their online lifetime:
USENET and Mailing List posting netiquette
Newbie Survival Guide to Mailing Lists