I have no authority here, and my judgement doesn't matter, but imo that rule was not intended to stop people discussing their own experiences, history, learning. It was just intended to try to avoid bad-blood about what was happening on PR becoming a defining feature of discussions here. It would be a shame if it led to us missing out on a lot of valuable discussions.
So does that mean @Sly Saint would be okay discussing their experiences on other forums and how they learnt more about Action for ME?
Yes, Rule 11 doesn't apply to behavior on remote platforms, so people can certainly discuss other forums elsewhere without facing any consequences for it here. From the Consequences of Rules Violations: So basically behavior elsewhere is only taken into account for serious and nasty offenses, and not in regard to rules which are more aimed at procedural matters or keeping things running smoothly.
But it wouldn't be okay to post about it here? Rule 11 is thought to apply to descriptions of how other ME/CFS patient forums helped develop someone's understanding by providing useful information, debate, etc?
Discussing other forums in a positive manner would be very likely to attract dissenting opinions, so all discussion regarding events on other forums is disallowed.