can anyone describe it for me
A vertical is a type of offer, basically.
So if you run lots of stuff in the "finance vertical" that might include life insurance lead-gen, refinance lead-gen, debt consolidation, etc.
If you are in the ecom vertical, that might be stuff like gadgets, health products like foot insoles, etc.
Gambling might be gambling apps, lead-gen for gambling websites, etc.
BizOpp (Business-Opportunity) would be courses teaching people how to make money doing x,y,z, etc.
It's kind of like a synonym for 'niche'.
Some people focus entirely on one vertical, some run lots of verticals.
Hope that helps 