In the internet world, when two businesses make an exchange of either services, information or products, this is considered B2B, or Business to Business. This is different from a business interacting with consumers. An example of this would be the manufacturing of a certain product. If one business contacts another business for specific parts or information related to the process of creating the product, this is B2B. The final product can then go on to be sold to consumers.
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Social media can be effective in the instance of B2B just like it is with consumer marketing. You can tailor your social media approach using the same outlets, just making sure that you know your audience and your targets.