I think that's not quite the correct question to ask. The question to ask is: what purpose will your new community website/app serve that is not already being m

I think that's not quite the correct question to ask. The question to ask is: what purpose will your new community website/app serve that is not already being met by existing ones? Here's one anecdote: personally, I haven't yet found anything that captures the feel or social vibe of early/mid-2000s LiveJournal. I think what another commenter referred to as "Single Player Mode" actually had quite a lot to do with what drew me to LJ in the first place - at least initially a lot of what it was about for me was personal blogging just for me, and I gradually explored other personal blogs and communities while I was doing it, eventually forming real friendships/relationships with other LJers.