The service describes itself as a “cross-platform mobile messaging app.” It works on iPhone, BlackBerry, Android, Windows Phone and Nokia — and those phones can all message each other.

It uses the same Internet data plan that you use for email and web browsing, so there is no cost to message.

In addition to basic messaging WhatsApp users can create groups, send each other unlimited images, video and audio media messages.

On its blog, WhatsApp insisted that nothing would change with the Facebook acquisition.

“WhatsApp will remain autonomous and operate independently. You can continue to enjoy the service for a nominal fee. You can continue to use WhatsApp no matter where in the world you are, or what smartphone you’re using. And you can still count on absolutely no ads interrupting your communication.”

“WhatsApp has done for messaging what Skype did for voice and video calls,” said Jim Goetz, an investor with What’sApp backer Sequoia Capital, on the company blog.

WhatsApp began notifying users last month of its updated terms of service and privacy policy, which people must agree to in order to keep using the app beyond February 8.Many users expressed concerns about a section of WhatsApp’s privacy policy that details what user data is collected and shared with parent company Facebook, which has a troubled reputation when it comes to protecting user data.All private messages between individuals and most businesses on WhatsApp are protected by end-to-end encryption, meaning the app can’t see them or share them with Facebook (users will be notified before chatting with a business where messages are not end-to-end encrypted). But WhatsApp does collect other user information, such has how and when someone uses the app, and user device information like IP addresses.WhatsApp’s privacy policy states that user information it collects may be shared with other Facebook companies “to help operate, provide, improve, understand, customize, support, and market our Services and their offerings.”However, these data sharing practices are not new, according to the company.

ere’s what has changed: WhatsApp’s privacy was last updated globally in 2016. At the time, it offered WhatsApp users the ability to opt-out of sharing data with Facebook, an option that was available for only a short time. In this latest update, the reference to that now-expired opt-out option has been removed.The more significant update to the policy relates to WhatsApp’s business users. It discloses that businesses thatuse WhatsApp to talk to customers can choose to store logs of their conversations on Facebook hosting services.”The update does not change WhatsApp’s data sharing practices with Facebook and does not impact how people communicate privately with friends or family wherever they are in the world,” a WhatsApp spokesperson said in a statement, adding that the company remains “deeply committed to protecting people’s privacy.”In short: No additional WhatsApp user data will be shared with Facebook after accepting the new terms than was shared before. That is, unless you took advantage of the opt-out in 2016.

WhatsApp has been trying to disspell confusion over the updated policy, including by publishing an FAQ on its privacy practices.