Facebook has become an 800-pound online gorilla… or, actually, a 400-million-active-user gorilla. And with half of those users logging in on any given day, Facebook claims a massive share of the English-speaking web population, and recently outpaced Google itself in traffic.

The problem is, they operate with neither accountability nor transparency. I’m finding stories like this are becoming way too common:

The folks at Social Media Today have an active Facebook presence, using a Fan Page. And they’ve recently been posting a link to that page twice a day. A few days ago, when they tried to post a link, they received a message from Facebook:

Block! You are engaging in behavior that may be considered annoying or abusive by other users.

You have been blocked from sharing web addresses (URLs) because you repeatedly misused this feature. This block will last anywhere from a few hours to a few days. When you are allowed to reuse this feature, please proceed with caution. Further misuse may result in your account being permanently disabled. For further information, please visit our FAQ page.

The problem, apparently, was they were posting links too often.

So how often is too often? Facebook won’t tell them. How do they need to change their behaviour to get link-sharing reinstated? Facebook won’t tell them.

Now, I understand that Facebook is a private company, not a public utility. They’ve built an enormous user base because they’ve built a compelling platform, and because they’re run by savvy businesspeople.

They’re also spectacularly unaccountable: a closed organization given to apparently capricious decisions. And that’s not a great fit with the Cluetrain era that Facebook is supposedly helping to usher in.

There’s an arguably even deeper issue. With so many people engaged with each other on Facebook, it starts to take on the role of civic space… where a lack of accountability and a Star Chamber mentality have larger social ramifications.

Whether that begins to make the case for some form of regulation – maybe along the lines of consumer protection legislation – is up for debate. But if Facebook’s lack of openness becomes an irritant for the broader user community, and not just social media professionals, then government intervention would be the least of the site’s concerns.