At the same time, however, I think it’s fair to ask how sustainable that recent growth is.

Let’s get one thing out of the way first: It’s great that the Washington Post is growing its readership, and it is using a lot of smart methods to do that, including understanding how social media works to its advantage. The New York Times is also doing this in a variety of ways. I am a big fan of both newspapers and would like to see both of them succeed.

Some of what’s going on between the Post and the Times is the media equivalent of rap-style bragging, with the Post needling the Times, including comments from owner and Amazon CEO Jeff Bezos about how he wants the paper to become the “new paper of record.”

Since the Post was seen as largely moribund or even in decline before the Bezos acquisition, it’s not surprising that it would want to celebrate its achievements.

But there’s a larger question underlying its recent traffic success, and it’s one that goes to the heart of the strategy that the Post has been implementing. It is this: If social tricks and piggy-backing on Facebook (FB) are the main reason why the Post has eclipsed the Times in web visitors, is that a long-term strategy? Or is most of that just low-value, drive-by traffic?

In a recent piece on the Post‘s growth, Digiday broke down what appears to account for the increase in web visits. Some of that growth has clearly come from technical solutions such as faster-loading pages and a better mobile experience, and from a hot news cycle involving the presidential elections, etc.

The paper has also done a number of smart bundling deals, including one that provides a discount to subscribers who are members of Amazon Prime, and one that offers it to subscribers of other newspapers.

A big factor in the Post‘s growth, however, is the way that the paper has embraced Facebook as a distribution platform. As Digiday points out, the Post’s Facebook traffic rose from 43 percent to almost 50 percent of its social referrals between May and October, according to online analytics company SimilarWeb. And a big part of that was “viral” content, as opposed to news.

It’s not just the content choices, or the way they are designed for sharing on Facebook. The Post has also gone all-in on Facebook’s Instant Articles program, in which the site hosts stories and optimizes them for mobile users. The Post is the only partner in the project that has agreed to provide 100% of its news output to the giant social network.

Cory Haik, the paper’s director of emerging news products, talked about this approach to the Nieman Journalism Lab—in a piece that also mentioned how instrumental Bezos was in getting the Post admitted to the Instant Articles beta.

As Haik described it, since the Post gets credit from comScore for the traffic to Facebook-hosted articles and readers get a better experience (because the pages load faster and are better looking), then it is a win-win deal for the company.

So in a nutshell, the Post is piggy-backing on Facebook’s massive reach to get its content in front of more people, and hopefully convert them into regular readers. Not that different from what lots of other companies are doing, including the New York Times, which is also a partner in Instant Articles, but doesn’t provide 100% of its content the way the Post does (Time Inc., which owns Fortune, is also a partner with Facebook for Instant Articles).

Is this a smart strategy? Clearly, it has benefits. More people might see Post content, and like it. They might seek the newspaper out, or develop feelings for the brand. And the paper gets to keep 100% of the advertising revenue for ads it sells, or 70% of the revenue for ads that Facebook sells.

So the Post gets readers and money. How could that be bad? I’m not arguing that it’s bad. Revenue and readership are both good. But if you are using a variation on clickbait headlines and aggregation of whatever hot viral content is going around (and the Post is far from the only mainstream outlet to be doing this), it’s worth asking what that gets you over the long term.

Do users click and get a quick dopamine hit from these posts and then move on, or is it possible to convert them into loyal readers? And if it’s the former, is the Post the one who benefits the most, or does Facebook ultimately become the news source that matters?

I’m not sure anyone knows the answer to those kinds of questions—I’m pretty sure that I don’t. And it’s worth noting that plenty of newspapers are (and always have been) full of the print equivalent of viral clickbait, whether it’s horoscopes, celebrity profiles, or gossip columns. That doesn’t necessarily stop them from being seen as serious journalistic entities.

But in a media environment that is already overloaded with viral content from a thousand different sources, I think it’s worth asking whether adding to that is serving a larger purpose. If your brand value is supposed to be filtering through the noise for people and showing them things that matter, does it help if you are also trafficking in whatever is clicky? Will readers be able to distinguish between what you use to drive traffic and what you see as your core value? I don’t know.

In the best-case scenario, the Post and other media outlets pursuing a similar strategy appeal to new readers and boost their revenue, both through ads and subscriptions. In the worst-case scenario, those traffic practices dilute the value of their brand until readers aren’t sure what to expect from them any more—plus they give all the power to Facebook.

At this point it’s a toss-up which of these outcomes is the more likely. All I know is that the second of those options is a tough place to try and come back from.

You can follow Mathew Ingram on Twitter at @mathewi, and read all of his posts here or via his RSS feed. And please subscribe to Data Sheet, Fortune’s daily newsletter on the business of technology.