The criteria for Monitors:
1. Current Activity in the area: For example, TL Updates, suggestions for Atlas corrections, PNR related queries, etc.
2. Current interests. What they want to do, etc.
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The aforementioned members...
more... are all very involved with TL Updates, PNRs, Atlas, etc., and have established themselves to be diligent, through their past activities. So they were made the respective Monitors, to empower them further.
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If you are interested in anything specific, you may pvt. post me about it, and something will be done to make your time on this site more worthwhile and interesting. Thanks.