Investment needs for online community
I was recently asked by a friend to help him judge an investment into an online community. This is far away from my usual work on mature companies so I'm looking to get some more insights into it. Unfortunately I can't disclose any details but let's just say it's a website focused on consumer electronics where they provide own reviews but also cooperate with producers of these products by providing market research for them etc. There are c.10,000 registered users and they want to scale it up quite significantly.
Now I feel ok about understanding or criticising their business model but completely lack an idea of how much it costs to grow a website / online community. I already looked at the huge communities like Facebook or Tripadvisor but that's not really comparable since we're talking about a different scale. Obviously there are costs for SEO, new staff, etc but are there some good examples you could recommend to learn more about the economics?
I'm open to all kinds of suggestions (targeted blogs, forums, TedX...), just trying to gather some of the wisdom of the crowd on here.
Thanks in advance!