The sponsored invitations will show up in the Invites section of BBM while the sponsored channels can be found in the Updates section. Right now, the testing is going on in certain Beta Zone versions of BlackBerry's messaging app.
Other changes in the Beta Zone version of BBM include the ability to purchase stickers from the new BBM Store, an increase in the size of attachments from 6MB to 16MB, Control Group notifications received independently of other notification settings, the ability to send pictures in multi-person chat, and the ability to view images in both portrait and landscape orientations.
So far, it is not clear when the update bringing these new features will be sent out to all BBM users.
Ads are being tested on certain Beta Zone versions of BBM