I've been on the verge of starting a local community. I'll do it one day soon.
When I do, I would start with a website/blog, probably using Ghost. Good community starts with good communication. Comments are just fine for initial community building. Once you have some traction, consider a forum.
Also, look into Front Porch Forum, they've been doing it their own way for years, it can work.
However, my unschooled child loves maths and has...and much more...he's now doing maths at uni. He's also so deep into the philosophy world that my mind hurts just reading the titles of the books he buys.
I wish I had the encouragement and freedom to explore without judgement when I was that age.
Depending on the school, the smaller settings, the different and wider range of activities and support available. I'm particularly attracted to the Montessori way.
I'm concerned about schooled kids not socializing outside of their direct age group :) There's been plenty written about how unhealthy and damaging it can be to only be in a peer group of people your own age.
Honestly, the socialization is a myth. Homeschoolers socialize with all ages, that's healthy and educational from a huge amount of perspectives. e.g: kids can be become leaders by supporting younger or less able kids.
For maths, but they pick it up pretty easily in day to day conversations and activities (ipad and gaming helps, imho)
My 11 year old went to school part time, lasted half a term, but his maths skills were on par with the kids there, if not better. He had never done any formal maths.
I only speak on behalf of our family, everyone has different experiences, but it's still important to recognise that life and education can be done differently.
This doesn't address the issue of whether teaching the way schools teach is actually not very effective.
Self directed learning (which is basically unschooling) is so powerful and it's not uncommon for kids to go from zero reading to reading thick books (like Harry Potter, for example), within 6 months.
Kids/people have to want to learn and it's hard to manage that in a school setting.
I know as an adult that I can't learn things that I'm not interested in, it's the same for kids. And the curriculum is generally not very interesting.
I write about community from lived experiences and reference my lived community experiences, it's the most authentic way to do it.
I'd actually prefer people don't join that community. It's a very special little place on the internet for me. And people that know me know understand it's got nothing to do with money, that it's a fun experiment and the money is just a way to attract the right kind of people and make the community a joy to run.
There are definitely nuances and unclear boundaries of where the boundaries between 'public' and 'community' are.
I think the more active building in public people feel it is a community, but it probably takes them a while to get there. Some people need extra support to get to that public stage, or need a more private space to talk about things they feel they can't do in public.
Part of building in community is to create a supportive environment to help them build in public better. For example, I often say tell people 'in community' that something they've just said would be a great tweet. They tweet it and then I share or jump in the conversation there too.