Vine reported the 13 million figure in early ne, when the app was iOS-only. You can probably guess what happened then: Vine rolled out an Android app. As predicted, Vine’s user base exploded. Vine also didn’t reveal how many of those 40 million users are active, which is a key metric pretty much every app uses to tout its success. Tens of millions of people have signed up, which is great, but how many of those people regularly post Vines? That’s the number we want to know. (Side note: Instagram also took a while to start disclosing monthly actives instead of registered users.)

The Android effect

There’s no denying that Vine is incredibly popular—in ne, it climbed to the top of the iOS store’s non-game apps, according to the App Annie Index. Instagram ranked at No. 5, but that could change when ly’s numbers are released—Instagram didn’t add video until the end of ne, the 3-year-old app has a more established user base than the 8-month-old Vine. Instagram now has 130 million monthly active users. Vine wasn’t even a blip in the ay store for ne, when it debuted on Android. That could also change when ly’s numbers are released. If Vine has a big showing, then it will become clear how important Android is to an app’s success. Now, 40 million registered users is nothing to sneeze at. Nearly a year after Instagram popped up in the iOS store, the photo-sharing app had only 10 million users. Of course, Vine has the powerful backing of Twitter to help it along—Instagram didn’t gain Facebook’s assistance until the spring of 2012—but the number is still impressive. Vine may in fact be winning the mobile video-sharing war, but until the app discloses the facts behind the numbers, all we can tell for certain is that Vine is far from dead.