One of the changes the shift to digital has brought to Public Relations is the blurring of the line between earned and paid media. In fact, to be completely up to speed, you need to add owned and social media to the mix as well, but the earned/paid issue seems to be the most difficult for for PR counselors to wrap their minds around.

The concept of earned media has been at the heart of PR for decades (at least, that part of the practice of PR that deals with media at all; not all PR is media-focused). “Earned media” even has its own Wikipedia listing, where it’s defined as “favorable publicity gained through promotional efforts other than advertising, as opposed to paid media, which refers to publicity gained through advertising.” That definition draws a stark distinction. If PR is in the earned media business, paying for it is wrong.

Digital and social media have changed that to some extent, but not entirely. The opportunities for media buys in PR revolve around raising the visibility of other kinds of content (earned, owned and social). A good example comes in the form of a tweet sent today by Chesapeake Energy.

The tale begins with a New York Times piece critical of efforts to produce gas from shale. Chesapeake Energy CEO Aubrey McClendon took issue with the piece and said so in a lengthy email he sent to the company’s employees.

The email was also posted as a note to the company’s Facebook page. And, as just about any company would do these days, the company tweeted a link to the note. But that’s where the story gets interesting. In addition to simply sending the tweet through the company’s Twitter account, Chesapeake Energy paid to have the tweet promoted.

Promoted tweets, in case you’re new to them, are tweets for which companies pay to have them show up as the first result on Twitter searches (of which there are something like 150 million every month). Promoted tweets aren’t cheap; the Wall Street Journal reports that companies pay up to $100,000 to promote their tweets.

While promoted tweets aren’t a direct parallel to Good Adwords, the idea is similar. When someone runs a search, the paid tweet gets elevated to the top, making it more visible. The fact that it’s a promoted tweet is clearly displayed, just as Google’s paid search results appear in their own distinct bit of on-screen real estate.

Savvy PR practitioners have been using Google Adwords for a while. For example, Nieman Journalism Lab wrote back in 2009 about how New York PR firm CounterPoint Strategies used Google Adwords to raise awareness of another group targeted in a New York Times article. Chesapeake’s use of a promoted tweet is pretty much the same tactic.

This isn’t the same as advocacy advertising, when Mobil’s Herb Schmertz famously (and controversially) blurred the lines by running paid advertorials on the bottom of The New York Times’ editorial page (and in other newspapers). The ads were meant to present Mobil’s perspective on the energy crisis. In the case of paid search, all companies are doing is using the means available to ensure there is a greater opportunity to discover the actual content that the company has placed elsewhere, without paying for it. And only people who are searching on relevant keywords see the Google ad or promoted tweet at all.

The placement of McClendon’s rebuttal on a Facebook page brings up one of the other types of media: social. Typically, a company would create a microsite or a page on its own website; in either case, the company would take advantage of its owned media. In fact, some would argue that there are sound reasons to skip Facebook and put the content where you have more control over it.

But placing the rebuttal on Facebook makes it easy for community to engage with it, which not only turns a monologue into a conversation, but could have an effect on whether it shows up in news feeds and gets even broader exposure.

Whether all this pays off for Chesapeake Energy will depend on factors beyond the channels employed. The accuracy of the response, how negative comments are handled and a host of other issues will determine whether the tactics pay off. But the approach the company took to getting visibility for its message and encouraging discussion around it was entirely appropriate in today’s media environment.

The fact that the Chesapeake Energy paid for the promoted tweet doesn’t make it any less a PR activity.