I've been reading HP Museum for several months now, but couldn't sign up until now due to lack of a working non-freemail address (required to sign up).
As much as I agree about TI websites mainly having younger users who are not as knowledgeable about maths, I think it's inevitable considering that most TI calculators are aimed at high school and university students rather than engineers. Same goes for Casio, so this is why not only they will get a younger audience, but they'll also be more oriented towards calculator hacking than educational calculator use.
For the HP Prime, it's inevitable that the same thing will happen, because unlike the HP 48/49/50 series, the HP Prime was primarily aimed towards hi-school/college/uni students, not professionals/engineers, in attempt to compete directly against the TI-Nspire.
However, what I always liked about TI websites that HP ones seems to lack (judging by the negative comments against the HP Prime wiki on TI-Planet and your post above) is that on TI websites, people won't constantly act like they're superior to HP/Casio sites, they won't bash any HP/Casio calculator site just for trying to expand towards other brands like I saw over here towards the HP Prime wiki on TI-Planet (see old Lionel Debroux topics), your HP/Casio calc collection won't be called junk and you won't get told to throw it away and only keep the TI's and people won't constantly brag about how their site userbase is superior to HP Museum.
In summary, while TI sites might have a younger userbase that is less focused on maths, I don't think it's that much worse than an older userbase of HP users that constantly engage into fanboyism actions and who want to keep the entire HP discussion monopoly and keep attacking TI websites that tries to expand their horizons towards other calculator brands (such as the negative remarks towards HP Prime Wiki for being hosted on a TI site and the remarks above about how TI sites have kids who have zero math knowledge, which isn't really true anyway, considering several users are close to 30 years old and need math knowledge in order to produce advanced programs).
Besides, there is a reason why TI websites have taken interest in the HP Prime: The TI-Nspire sucks. Obviously those websites aren't gonna close shop just because one HP website userbase is angry that HP Prime discussion occurs elsewhere, and constantly attacking the TI community for budging on your thunder or for their lack of math knowledge/too high focus on calculator games is not what will encourage those people to participate on HP Museum. They'll only see the site as a walled garden of haters.
(By the way, I love my HP Prime. I hate the bugs but I'm glad that HP fixed many of them in the recent update. I hope to see an HP 51g or a major HP Prime upgrade that brings back all the 50g features.)
Edited: 6 Dec 2013, 1:56 p.m.