WhatsApp's active user base could be a cause for worry among some tech companies and wireless carriers.
The messaging service announced Thursday that it has more than 250 million active users -- making it on par with Skype, Facebook Messenger, and Twitter, according to The Wall Street Journal.
Twitter's most recent numbers show more than 200 million monthly active users, while Skype's are 280 million and Facebook Messenger's aren't reported but its app is ranked sixth in free apps in Google Play, according to the Journal.
In the U.S., WhatsApp is ranked first in paid apps in the iTunes Store and 31st in free apps in the Google Play Store (the app costs 99 cents for iOS and is free on Android for the first year, and then costs 99 cents). During the AllThingsD mobile conference in April, WhatsApp CEO Jan Koum hinted that the service had surpassed Twitter's active users.
Wireless carriers make a big profit on text messaging, and apps like WhatsApp are eating into these earnings. Since WhatsApp offers a free alternative to texting, users don't have to pay for each message. According to a report released in April by research firm Informa, text messaging is on the decline due to chat applications becoming users' preferred method of communication.
However, Koum said during the AllThingsD conference that carriers could easily turn around and see his business as driving data adoption. WhatsApp, Koum said, has participated in a number of carrier partnerships that further drive adoption and usage, including local data deals in India and access to a "roaming pass" with a partner in Hong Kong, allowing users to travel elsewhere in Asia and still use WhatsApp without extra fees.