I just returned from spending a couple hours with IABC‘s staff talking about content curation as a new skill and responsibility of communications professionals. I tweeted that I was headed into San Francisco for the lunchtime meeting, prompting a reply from web consultant Ramsey Mosen asking my view of the ideal balance between curated and original content.

It’ll come as no surprise to regular readers that I replied with “It depends,” which is both accurate and a cop-out. On what does it depend? And based on those factors, what is the appropriate mix?

One of the best laughs I’ve had recently (at someone else’s expense) came from a blog post that advised Twitter users to apply an exact division of categories of tweets: x percent for links to your own content, x percent for links to other content, x percent for personal observations, x for retweets, x for participation in conversation and so on.

I can think of few activities less worthwhile than calculating the percentage of tweets that fall into each category in an effort to make sure you’re getting it just right.

The very idea that you can apply a formulaic approach—for tweets or a curated-to-original content ratio—is ridiculous. You need to consider the various factors at play in your communication efforts—audience, niche, objectives, and so on—to figure out what’s right for you or your organization, then strive to come reasonably close.

Consider Todd Defren’s recent post suggesting that heavily-regulated and social media-phobic pharmaceutical companies can get into the game by curating other people’s content. If a pharma takes Todd up on his sound advice, then 100% of the company’s social media content would be curated.

(Incidentally, there are plenty of other opportunities for pharmas to engage in social channels without stepping over the regulatory line.)

IBM curates content related to its “smarter planet” initiative. Using as Tumblr blog, the site serves as a repository for material IBMers have found that relates to the campaign. IBM creates a ton of original social content as well. The curation effort represents but a tiny fraction of its content, but it still serves a useful purpose, aggregating material interested readers might otherwise never find, providing context for the articles and authenticating them.

The right amount of curation, then, is the amount that serves your audience’s needs and supports your organization’s objectives—the same criteria you’d apply to determining the right amount of original content. If you adopt that approach, you won’t need to worry if your curated content begins to exceed the volume of your original content.