B2B Digital Marketing

B2B basically means business to business, it is the exchange of products, services or information (aka e-commerce) between businesses, rather than between businesses and consumers. It helps in lowering the cost for selling and marketing but the most important advantage of B2B is to have just in time (JIT) delivery, the company can have the track of good as to which place it has reached with the help of electronic commerce.
So does that mean digital marketing companies can help both B2B and B2C? We're considering hiring DemandWave to help with our business and when I checked their website, it looks like they can work with B2B just fine. Any tips on what we should looking for in a digital marketing company?