Sorry, a bit late to the party on this one. I fully understand your idea and see where you're coming from.... it's just one of those things that I don't think scales up well. The struggle to get a critical mass of businesses signed up would be huge in itself - if you do achieve that, then the potential for huge amounts of spam, fake profiles, influencers offering to charge for promotion, etc etc would just be huge.
I also think you're giving people too much credit by sort of saying "I'll connect them, then they can work a deal out". They might not have the nouse or knowledge to come up with something appropriate and potentially get taken advantage of, or just end up with a bad experience so they never return to the platform. I think they'd be expecting more from your services.
I think this has more legs. Essentially setting yourself up as an agency but specialising in connecting businesses and cross promotions - i.e. relatively "low cost" marketing possibilities for your customers. Could be a nice little niche.