I started writing this as a forum reply for this thread but I went a little long so I thought I’d give it a proper home and kickstart my blog.
BP and MU and Plugins and Themes. It’s never really going to be perfect as you say, at some point you have to step back and stop adding the plugins and all the cool new features that you read about at the forums…and get focused on your community and start working on a story for what you’ve built. Because the nature of constructing something we these tools is that its easy enough for the next guy to build something very similar and odds are for many your sites will look and navigate very similarly from the get go (so try to deviate as much as you can from the prepackaged look of a bp site when you’re building).
So what is the story? Your story becomes very important especially in the general market. You have work harder to set your self apart from all the similar looking bp sites and blogs even. Your story starts with you and with the niche you’ve built your site for. who are you, what is your site and why is it important for me to know about both. Make it clear that its not meant to be a replacement for larger, established networks. Get your story to the shakers in your niche, get to know them, get them involved in the site and they’ll start talking about you and supporting you. Think of coming up with a story as coming up with a gimmick but not so gimmicky! It’s a narrative and ultimate about page.
As for lack of activity, that is a very big deal. So that’s where those beta testers, friends and shakers come in. Get them to create activity very early and a lot of it. Think about a restaurant. How do you gauge whether or not its good? Are there a lot of people inside eating or not so much. Perception. DO NOT create fake users with fake activity.
As i said in the beginning there are going to be bugs, never going to be perfect if your small time, once they know your story of being “a DIY little guy” invite the community to be part of the building and creative process of the site thru a blog blog, add report-a-bug links, give error page, nice looking error messages. When there is an error or down site, ask for forgiveness and give credit to the user who pointed it out, send out plain text letter emails directly from you the founder not “The Team” and user will be a little more forgiving of stuff that doesn’t work and they’ll come back. If they feel like they are part of a neighborhood and they’re chipping in for the success of that neighborhood, that goes a long way.