Wa Alaykum Salam,
The scheme or method used by them is not gambling nor is it interest based so the income in general would be Halaal. Don't stop reading here...
However, if the adverts are Haraam in contents such as gambling sites, dating sites etc or requires or promotes/invites towards Haraam activities or viewing of images/videos etc then it should be avoided.
For any specific cases or rulings, please ask in the Q&A section
www.muftisays.com/qa/askmufti/
Wassalam