Popular cross-platform messenger WhatsApp has found a home on hundreds of millions of smartphones, and in the process has surpassed some other widely-used communication tools. On stage today at D: Dive Into Mobile, WhatsApp CEO Jan Koum said the company now boasts a bigger base than Twitter, which claims 200 million monthly users. And the company now processes some 18 billion messages a day, while by comparison, Facebook is processing a mere 10 billion. Unlike Twitter and Facebook, the app has also eschewed traditional advertising, and is transitioning to a $0.99 annual subscription model across all platforms.

"You don’t want to be interrupted by ads when you’re chatting with your loved ones."

"We do have a manifesto opposing advertising," Koum said at today's event, according to a report in All Things D. "We’re so bombarded with ads so much in our daily lives and we felt that smartphones aren’t the place for that. Putting advertising on a device like that is a bad idea. You don’t want to be interrupted by ads when you’re chatting with your loved ones."

Despite the move to a paid model, Koum said that WhatsApp hasn't seen a drop in users. All that said, we don't know exactly how many users WhatsApp has, or even how many more people are on it than are on Twitter — Koum wouldn't say. But WhatsApp's momentum is undeniable, which has led it to be the subject of frequent acquisition rumors. (Those rumors have been quickly shot down by company.) "Our goal is to build a sustainable, independent company," Koum said. "We want to build a business."