I built https://communiroo.com because I couldn't find a quick and simple single website to expose bug/feature tracking + SO type questions + forums + support requests for my other things I was building. It seemed (and still seems) like it fills a need for mine and everyone else's side projects.
I think the biggest issue is marketing. I tried a few Twitter/Facebook ad campaigns that didn't really pan out, and an HN submission that didn't make the front page. But really I haven't done much to market it, and it just sits there chugging along with few users other than myself while I work on other stuff.