Social media guidelines for employees can be a contentious issue. While a cultural shift in behaviour means that fewer companies are forbidding their employees from using Twitter these days, some still struggle to find the balance between total freedom and overbearing policy. 

This is why I rather like the guidelines that the British Society for the History of Science* have set out for their conferences, which I think apply very neatly to more general best practice for professional social media behaviour. You can see their full points in the link below, but here are my translations of each in a B2B setting:

• Conduct yourself with others as you'd like them to conduct themselves with you. There's a human behind that profile you are tweeting to.
• Don't just promote yourself/your work, share interesting content written by your colleagues and other professionals in your field too.
• Stay courteous when commenting, querying, or giving constructive feedback
• Avoid alternative facts and/or sharing publications that are from disreputable sources
• Check before sharing that the content isn't sensitive in nature (is it officially released for instance? Does it contain information not intended for the general public? Are you breaching confidence?)
• Do include the Twitter handles (or tag the person on LinkedIn) if you are talking about their content. 
• Use relevant hashtags (particularly when at events)
• If you are going to comment on someone, make it about their research and ideas, not their physicality or way of presenting themselves

*I presented a paper there a few years ago on the spectacle of science in French Revolutionary prints. Once a geek.... If that kind of stuff interests you, I have a chapter on it in my book here.