As the adage goes: "If you build it, and then force people to download it, they will come."
Or something like that.
At least that holds true for Facebook. The world's largest social network said on Monday that over 500 million people each month use Messenger, Facebook's standalone messaging app. That's up from 200 million people using it each month in the first quarter of the year.
The accelerated rate of adoption -- Messenger was first released in 2011 -- comes after Facebook essentially forced people who use Facebook on their phones to download a separate app if they wanted to keep sending their friends messages. You can still send messages just by logging into Facebook from your PC.
Messenger still isn't as big as WhatsApp, the messaging service Facebook bought for billions earlier this year. Six hundred million people use WhatsApp each month, according to a tweet from Jan Koum, co-founder and CEO.
Facebook says that the Messenger standalone app is a better "experience" for people who use Facebook on their mobile devices -- it's faster and has more features than when it was part of Facebook's mobile app. Mark Zuckerberg, Facebook's CEO, said last month in a call with investors that people who use the app reply to messages about 20 percent more quickly than those who don't.
One of the main reasons Facebook "unbundled" Messenger (and has released other apps, too) is to protect itself, in case Newsfeed, which is the main reason people use Facebook, begins to wane in popularity. If you start logging into Newsfeed less, then Facebook hopes you'll still use Messenger to communicate with your friends. That won't come anytime soon, though -- the company reported last month that 64 percent of its 1.35 billion of its monthly active users log-in to the service every day.
As Quartz's Dan Frommer wrote after the company announced its latest numbers, "Facebook is more addictive than ever."