The day many advertisers have been waiting for is here. Facebook is finally allowing ads directly in Facebook messenger. This is going to change a lot of things, both for better and for worse.

Facebook has already tested their new ad feature in Thailand and Australia and reported that the yield of their study has been mostly positive. This is why  they are now enlarging their display ad channels with a beta version that lets business pages purchase media space between private chats. On paper, this sounds like an invasive, annoying thing to do, but Facebook assures everyone that it will be executed in a very tasteful manner. This month we will start to see ads in the messenger app home tab. And more and more of this will be gently rolled worldwide out through the year.

So just how will these ads be served and will they be as annoying as they sound? Facebook claims that the number of ads in a person's inbox will be determined by hoe many chat threads that person has active, how big their screen size is, and also, even the "pixel density" will be checked as a factor. As for invasion of privacy, Facebook claims that the ads will not target users based on key words within the chat itself. But of course, that sounds a little hard to believe. If that's not the case now, we may see things change in the future.

The ads will of course be available to businesses through Ads Manager or Power Editor, and it will be one of the default placements for ads aside from Instagram, Audience Network, and the main Facebook app.

The design of the ads has changed from horizontally scroll to single display. The reason? People might accidentally click on the ads because Messenger is designed for swiping.

Facebook has been running out of ad inventory space in its News Feed as more and more advertisers are competing with content. To avoid this slowing down of ad revenue, of course the company needs to compensate by finding other locations in their properties.