Snapchat was the biggest winner the day Facebook's services went down

Snapchat use surged more than 20% after Facebook Inc.’s services went down for six hours Monday, the biggest winner among rival apps during the U.S. social media giant’s worst outage in years.

Facebook blamed network configuration glitches for immobilizing a suite of apps from Messenger to Instagram and driving some of its 2.7 billion daily users to the competition. Snap Inc. saw a 23% boost in time spent on its Android app on Monday compared with the same day the prior week, according to Sensor Tower data shared with Bloomberg News. That led gains in activity on apps from Telegram and Signal to Twitter Inc. and ByteDance Ltd.’s TikTok on Oct. 4, the mobile researcher said.

The service disruption, which Facebook blamed on a faulty network configuration change, hit small businesses and gave ammunition to critics and legislators arguing that the company has grown into an unwieldy monopoly that should be cut down to size.

Telegram founder Pavel Durov said his app added 70 million users and set new highs for registrations and activity on Monday. It jumped to the top of the iPhone App Store as the most-downloaded free app in 40 markets, while Signal was no. 1 in Poland and in the top 10 in 35 markets, Sensor Tower said.

Alternatives like Telegram, which closely matches the look and functionality of WhatsApp, have historically added millions of users every time the world’s most popular messenger has had a significant outage, though many quickly return to the Facebook app once it’s back online.

“We’ve spent the past 24 hours debriefing how we can strengthen our systems against this kind of failure,” Facebook Chief Executive Officer Mark Zuckerberg wrote in a note to employees on Tuesday. “The deeper concern with an outage like this isn’t how many people switch to competitive services or how much money we lose, but what it means for the people who rely on our services.”