Sorry you are new and getting this response, welcome to UP. You have a referral number and can earn a bonus if you recruit new riders or drivers and they give your info. You don't want to recruit drivers because #1, you would have to lie to entice someone into this job and #2, you're giving yourself even more competition in an already saturated market. No, no no!!!
I've heard some hand out these cards in various situations to recruit riders, but that seems like pretty lame behavior to me.....I, for one, would run the other way.
So what is being said here is there's no deal with these cards...don't waste your money.
I'll exchange cell numbers with area airport business travelers who express an interest in a 'regular' driver to the AP. That's really the only time a personal business card would come in handy. I haven't bothered.