Trends? “Let’s develop a community,” they say, meaning an online community. Search google for let’s develop a community and you get 23 million hits. You tell me: is there a marketing meeting brainstorming web opportunities that doesn’t include an online community?

So, contrarian hat on my head, I want to list some reasons not to develop that online community you and your team have been talking about. I don’t want to be negative … but still …

1. So many communities already.

How many logins can anybody manage? We’re lost in a sea of communities. Each assumes we’re going to log in regularly, check messages, look around, see what’s new, respond to people, and interact. Realistically, though, how many times are you going to do that in a single day?

We’re dealing with several hundred already-established social media communities. There’s Twitter and Facebook and LinkedIn, plus all those others. And then there are those school sites, alumni sites, home town sites, media sites, fan sites, in sites, over sites, and hind sites … never ending. Who can deal with that?

2. Ning, a cool idea, grows up. And gives up Free.

Do you know Ning? One of Marc Andreeson’s brainchildren, it produced hundreds of millions of dollars for its founders, and countless similar-look-and-feel community sites that all did one version or another of community, with log-in, profiles, friending, posting, and so on.

I’ve had notice in recent weeks as one after another of those sites closes shop. Ning is focused on the corporate enterprise market, where there’s money to be billed. And all of those community sites were competing with all of the other ones for your and my limited time available. It wasn’t working.

3. Oh the spam! The never-ending spam!

I’ve been involved with maybe half a dozen serious efforts by major business media and related organizations to build an online community of entrepreneurs, small business owners, and assorted interested parties. I won’t mention names here because I’m involved with most of them, like the people, would like them to work; but they don’t.

The self-serving shallow sales message, some of them thinly disguised, most of them blatant, end up flooding these sites like sewage from a failed treatment plant. Who wants to look at messages when they’re all that? The supposed or alleged interaction, the likes and votes and all, are similarly polluted with commercial sludge. It’s a shame, but it’s also reality.

4. Those disappointing messages.

The business community sites are also flooded with messages that ask authors and experts to summarize, presumably in a couple of paragraphs or so, the thousands of pages already published on that same topic. I know these people mean well, and I like to answer questions. But it would be a lot nicer if they’d look at the site they’re on first, rather than just asking for a three paragraph summary of 50 good pieces already posted.

I get it. They’d like to have it all in a personal message. But it isn’t really that simple. It takes reading all the ins and outs and on the other hands. So that email doesn’t work. And the authors who get it are disappointed, because they thought they’d already answered that question, and put it on the web where people could get it.

5. The molten lava landscape is cooling into solid ground.

I doubt it’s coincidence that two of the three Ning sites I think of first are giving up the Ning model and moving over to Facebook like instead. It’s human ability to support so many different motifs that ends up pushing us all towards a few big ones. With Twitter, Facebook, and LinkedIn, we have consolidated logins, comments, links, suggestions, and updates.

It seems to happen a lot. The winners emerge, the also-rans fade, and the business landscape solidifies.

Please, don’t do that online community you were thinking of.

Do, however, focus on one or more of the already-existing online communities and make it work for you, and your business.