I'd like to debate this further. In my eyes you can't equate blackmail and Doming. If you need to resolve to blackmail to top someone, then you're not much of a Dom in my opinion, because Doming someone (for me) isn't about you getting the upper hand over someone, but that particular someone giving you the control willingly.
Oh yes, blackmailing has nothing to do with a D/s relationship in my opinion.
I agree with both opinions above. One had absolutely nothing to do with the other. Of course, I'm speaking of RL, and I quite realize that we, as writers of fiction, can pretty much do anything we like. But anyone who thinks blackmail has any place in a D/s relationship has a skewed misconception of what a true Dom/sub dynamic is all about.
Not speaking RL at all, from my side (If people were using this IRLwise, then I think police needs to be involved).
Most RPs I had that had a D/s topic were pretty far removed from any reality (usually fantasy, or modern times Vampire themed), with the addition that they are often dealing with NC themes, which usually makes it a tool that can be used to enhance it.
Plus, it is more something that allows a switch / another dominant character to give in for a time without giving up their position and their reputation in settings where both would be seen as important.
Example:
Powerful Lord/Lady of a small kingdom has a little secret that would endanger his/her position, falls into the hand of a thief who makes healthy use of it by bending the Lord/Lady to their will. Especially in an RP that involves more people this will not erode the Lord/Lady's position and power because it was not given freely, which would be actually submitting. It allows one character to give in, without actually giving in.
It is pretty easy to use in an NC game.
Another example:
In another RP, I had a character who was switchy, somewhat of an defiant sub, who constantly fought against his Mistress. Now, he was stronger, more skilled, and had better tools at hand, so she instead used her smarts to bend him, by finding out about my char having a lover. By using that knowledge, she could have him submit to her, without actually doing it. He hates her, but starts to like her touch. It's a means to drive the story and the whole D/s angle here. Plus, power exchange is hot.
Again, none of this should be confused with IRL D/s, at all. But it can have a firm spot in Non-consent D/s scenarios which play with the topic. First you make em stop fighting, then you turn em into yours. Especially if you rather enjoy your targets fighting spirit and fire.
So, I think it really needs to be specified between "Normal" D/s and D/s as used during Non-consent scenarios, which have a somewhat different goal.
I would agree that 'Forcing' someone in a consensual scene would be pretty epic fail, but D/s in Non-con definitely is different than in RPs where there is consent between Dominant and sub.
Now that I think about it... I cannot remember any RP I've ever read or done which involved blackmail, that was -not- NC focused in one way or another, which is why I assumed that the example given was of such an RP.
I apologise.
I should have clarified this all from the beginning.