Mindspring, I haven't read that in a long time.

Didn't they try to come back as a brand when free ad-supported dialups became a thing for a bit?

I dunno. I left around 1999, just before the EarthLink merger.

Related, while doing a quick search to see if I could learn anything about what you described I found Wikipedia quoting NYT as writing about EarthLink in 2000: "second largest Internet service provider after America Online". I guess it was around y2k when aol finally got its ISP (and this its "world's largest") designation by the world at large. :)