Hard agree, building a community takes year and you have to be constantly available. You're the one who's going to do most of the talking for the first few years so you better be more skilled than 90% of the people who join if you want them to find value in it. Can't speak on ROI, mine isn't business focused but I'll say it's a great way to meet interesting people, especially if you're not the outgoing-type because it forces you to be.