From my point of view, the current standard in social media platform for B2B activities is linkedIn. They have features like:
Sales navigator to target specific companies and find relevant leads
Professional finder for human resources management
Advertising where you can target particular positions in a company
I believe it is a common practice today to search for a specific name on social media for a person or company to understand the background it has and find how you can get in touch with them. Also, I see there are social B2B platforms that promote online communities of researchers, innovators, technicians and entrepreneurs baset on previous experience and skills that are available at the national level (https://www.brainmap.ro/).
I recommend the following articles:
Article Reflections on “Social media: Influencing customer satisfact...
Web presence is must. For B2B being on linked-in is very important. I have experience of working with some companies, they use social sites to interact with decision makers. Some Chinese B2B agents are also knocking the Facebook accounts of decision makers. Below book addresses both B2B and B2C scenarios in context of both online and offline channels
Book Customer Experience Management A Handbook to Acquire and Ret...