NEW YORK (AP) — Facebook has bought TBH, a teen-focused app that lets people give anonymous compliments to each other through polls and messages.

Facebook on Tuesday confirmed the purchase, announced on TBH's blog, but did not say how much it paid. TBH, internet-slang short for "to be honest," says more than 5 million people have downloaded its app since it launched on Aug. 3.

TBH, which is only available for Apple devices at the moment, will continue to exist as a stand-alone app.

Facebook, based in Menlo Park, California, also owns Instagram and WhatsApp and has tried and failed to buy Snapchat several years ago. The latest acquisition is consistent with its strategy of buying — or copying — rivals, especially those popular with young people.