First of all: this is wild! I literally just had the time of my life reading those links. What an odd phenomenon.

Secondly - I'm okay with accepting Babysitter's Club. With this series - a weird duck indeed - I think considering the different series separately is a good compromise, if you're okay with that. So considering 'Confidential' as a continuation of 'High,' that would disqualify those books specifically. But if you nominate the other ones - 'Junior High,' 'Twins,' etc. - I'll accept those.