Well, we first need to understand that there are precious few concrete rules with which to comply. We each need to develop our own practice.
Notice that each of these light bulbs is transparent, but different. I see each B2B Marcom professional crafting their unique brand of transparency. Transparent (not always!), and different.
To help us learn from each other, John Cass and Toby Bloomberg tapped their extensive network, solicited expertise and opinion, and shared it with us. Review the 30+ Diverse Opinions On Social Media Transparency for yourself in Toby's blog or in John's blog.
In this piece you'll find several views, from many perspectives. There's even some input from yours truly, Rick Short.
Anyone involved with Marketing Communications will find something interesting, maybe even valuable, in this collection of thoughts, opinions, and firmly-held beliefs. Rather than tell you what to think, I suggest you dive into the party, then form your own opinion and practice. Ultimately, put it to good, ethical use and let your bulb shine brightly.