Credit Karma has exploded into a $4 billion fintech — here's an inside look at why it's leaning on influencers to court millennial and Gen Z users

· Credit Karma, long known for its free credit scores, launched as something of a marketing firm, connecting its users with credit cards and loans and getting paid by the banks that offered those products.
· Reports from the Wall Street Journal and CNBC have pegged Credit Karma as a 2020 IPO candidate, though its CEO has said...