AROS has mailing lists, IRC channels, etc... as does OS4 (perhaps less so with the mailing lists). Forum activity represent a fraction of the total discussions, I agree with that, but they can still illuminate the general trend for activity. MorphOS has a nice advantage in that the cost to start using it is cheaper than OS4, which of course helps with impulse purchases, but how many of those impulse purchasers then use it regularly. That seems to be a valid question to make if we're talking about 'active' users rather than just 'users' in a looser sense.
I don't know why, but I can throw in another variable here. Perhaps we can call it website allegiance or website familiarity and the comfort that offers.
The OS4 team has been trying to move postings (for purposes of support) to the Hyperion specific product forums.
http://forum.hyperion-entertainment.biz/Why doesn't everyone who is a customer follow the prompts from devs and testers to do so?
Imo, many folks see AW and Amiga.org very much like home, and are hesitant to sever themselves from that pleasant sense they get when they log into "home".
All I'm getting at with this comment is that there are other factors like the above, which I believe lead people to choose where to be active.
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