I've recently been asking people if they're using Meerkat or Periscope. “What's that?” is generally the response, and it's no wonder, as less than 1 percent of iOS users are using these new video apps, according to data from 7Park. That is in comparison to Snapchat's reach of nearly 30 percent. “Reach,” in this case, is the percentage defined as active monthly users of the app versus total iOS users in the U.S.