Chaosmancer
Legend
3.0 Deities and Demigods page 25 is where the description of divine ranks has the statements about ranks and worshipers progressing from demigods with hundreds to thousands of worshipers to greater deities who "may have millions" that both go up until you hit over-deity status.
Pages 12-13 discuss options in setting up the cosmology for whether gods are dependent or independent of worshippers for their power and the behind the curtain sidebar for the default 3.0 setup (Greyhawk) says: "The deities of the D&D pantheon are independent of mortals for their power, though it’s clear that many use worshipers to augment their power. Deities such as Corellon Larethian, Garl Glittergold, Gruumsh, and Yondalla are deeply concerned with their worshipers and undoubtedly draw some power from them. Boccob is infamous for his indifference toward worshipers."
I feel the page 25 numbers of worshippers could be decent for their optional cosmologies of dependent gods where the numbers could represent direct power correlation, but they are a particularly poor match to Greyhawk where the greater gods have 1e-3e historically been noted for their remoteness and indifference and mostly there is no correlation to deity power.
1e WoG Boxed set page 62:
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I agree, which leads to a problem for @Maxperson
He has insisted that the number of worshipers must matter for your power/status as a god.
Except for Forgotten Realms, where what really matters is AO saying you are a god.
And except for Greyhawk which specifically stated that it was exempt from these rules.
And except for Eberron which works entirely differently
And except for Dragonlance, which also works entirely differently.
So, it seems to be a rule set that was never actually applied to any official settings.