Online discussions and debate rarely seem to lead to a wholesale change of anyone’s opinion. But I don’t think that should necessarily be the aim. A meaningful discussion should lead to something worthwhile being learned - whether that is about the issue at hand, about yourself, about the person or viewpoint you are arguing against - and/or some refinement of the views you hold. I really liked what Karl Popper said in this regard:
“…victory in debate is nothing, while even the slightest clarification of one’s problem - even the smallest contribution made towards a clearer understanding of one’s own position or that of one’s opponent - is a great success. A discussion which you win but which fails to help you to change or to clarify your mind at least a little should be regarded as a sheer loss….
Rational discussion…does not aim at conversion, and it is modest in its expectations: it is enough, more than enough, if we feel that we can see things in a new light or that we have got even a little nearer the truth.”