The document, obtained by a tech website, read, "Businesses will be able to send ads as messages to people who previously initiated a chat thread with that company. To prepare, the document recommends that businesses get consumers to start message threads with them now so they'll be able to send them ads when the feature launches".

The document also notes that Facebook has quietly launched a URL short link ''. However, it does not open and says Page does not exist.

"We do not comment on rumour or speculation. That said, our aim with Messenger is to create a high quality, engaging experience for 800 million people around the world, and that includes ensuring people do not experience unwanted messages of any type," the website quoted Facebook as saying.

Facebook is not going to let brands send ad messages to just anyone or even people who have liked their Pages but to only those who have voluntarily chatted with businesses.

On Wednesday, micro-blogging website Twitter said it is bringing video support to Direct Messages to iOS and Android smartphones.

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