There are a lot of things we need help with to craft lives for ourselves that will be both fulfilling for ourselves and useful for our societies. There is also a lot of help we have to *offer* that could help someone *else* fulfill themselves and make themselves useful. This is where we exchange offers and solicitations for such help.
Housing and Household Assistance: 
Many of us need places to live, or want to move out of where we are now. Sometimes unconventional options such as microhouses exist; sometimes the one of us in need has enough money that all they need to do is find a place to buy. Many of us would like to live in collaborative or cooperative households, so we can have friends around us and also enjoy the economies of scale of living in a larger social unit.
Economics and Activity: 
These two topics between them cover what used to be called "jobs". It's necessary to have resources with which to live, and it's necessary to have something to do. Sometimes these are linked.
Food, Farming, and Gathering: 
I suppose this set of topics should also include hunting, but at the moment I don't know any active hunters-for-the-pot. We need to eat. Where do we get safe, unpoisoned ingredients, and how do we go from that to being able to share wonderful dining experiences with our friends and families?
Even a great walker has a lot of trouble covering more than 20 miles in a day; we need better than that. Something like Larry Niven's 'stepping disks' would be ideal, but is far fuzzier in terms of application than even the White/Alcubierre drive mentioned elsewiki. So we cover who has what kinds of transport to offer, who wants to get where and needs help doing so, and who's creating toys or tools to help people move. (Velomobile and Zeppelin projects go here, as do ride-shares and automobile restorations.)
Having to deal with the vicious, murderous greed of the default culture is emotionally taxing. We need to both offer and receive assurances that there are people who will help us and offer what comfort they have.
Schools can still be of some use, but now that we have things like the internet and MIT's online study programs, an autodidact can get up to doctorate-level on their own as fast as they can read. It's still often useful to have study-buddies to discuss it with.
This *can* be related to 'emotional support', above, though introverts tend to do their centering by themselves rather than in company. Part of 'who we are as individuals' is 'how we engage with others', so even introverts sometimes need a hand in making sure they don't calibrate themselves out of society entirely.