When it comes to digital media, there are two things that are driving the transformation of the marketplace — namely, the rise of mobile and the growth of video. And at the place where those two things overlap, one of the names that stands out the most is Snapchat. The ephemeral chat application, often dismissed as a toy, is quickly becoming a serious player in video.

According to a recent report in the Financial Times, Snapchat’s video views have more than tripled in the last six months, and the service is now getting around 6 billion video views a day.

If true, that would put it within shouting distance of Facebook FB , which said recently that video views have doubled in the same period to about 8 billion views per day. The Snapchat figure is even more impressive when you consider that it is mobile only, while Facebook includes both mobile and desktop traffic. At 100 million, Snapchat’s user base is also one-tenth of Facebook’s.

It’s not clear where the 6 billion figure for Snapchat came from, however. The Financial Times quotes anonymous sources “close to the company” in its report, and says that a spokesperson later confirmed the number.

It’s also not obvious what Snapchat means exactly when it says “video view.” Facebook, for example, considers a video clip to have been viewed — at least for advertising purposes — if a user is exposed to it for three seconds. Many of Snapchat’s videos, especially those created by users, are only a few seconds long. The company reportedly charges advertisers based on fractions of a second.

The issue of what counts as a video view is hugely important both to the media industry and to tech platforms like YouTube GOOG and Facebook and Twitter, because that’s where a significant amount of the growth in digital advertising revenue is coming from.

A recent post by Joe Marchese of Fox Networks noted that while Facebook, Snapchat, and YouTube are seen as the main beneficiaries of a move to online video by millennial audiences, that picture can be deceiving, because their video-viewing numbers are inflated when compared with more traditional sources such as cable television.

A million minutes of viewing on YouTube, in other words, is qualitatively different in some sense (or should be) from a million viewers of an NFL game. And YouTube counts a view as anything after 30 seconds, compared with Facebook’s three seconds.

Complicating the comparison in Snapchat’s case is the fact that most of its videos also disappear once they are viewed, a feature that helped the service become one of the leading proponents of what some called “ephemeral messaging,” where photos and videos automatically vanish after a specific period of time.

Snapchat has been branching out from those ephemeral roots for some time, through the addition of features such as Discover — the media hub where partners such as CNN and BuzzFeed share their video clips.

Another feature that has become hugely popular with users is Snapchat Stories, which collects clips uploaded by users around various news events and locations. The service has said in the past that some of these stories can get tens of millions of views in a matter of hours.

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.