Yes, to a degree.
This is not to be mistaken for my having had my mind changed on a particular issue altogether, or that someone made such a convincing argument I renounced my previous beliefs.
However, I have had my mind changed - or altered - in ways that some people have made me think about certain issues in different ways, through different perspectives; which has often resulted in me becoming more informed on the subject, although often finding myself to disagree with those people even more. But that is "change" all the same.
There are some individuals with whom I have come to learn a lot (ObsceneWish shared many book recommendations with me a while back, and I have since come to learn a lot from many of those books/authors).
I have also learned a great deal in terms of how best to present information or arguments, how mentally debilitating the left/right paradigm is (for those on the left AND right), and how utterly ignorant or outright INSANE some people are in their beliefs. I am sure the same could be said for me, but I always flash on a moment in the forums where I remember Red Vespa or whatever his name is now, saying that a "solution" to the Afghan war would be to nuke Afghanistan... and I remember having had my hope in humanity sink a little by reading that comment as a somehow "legitimate" perspective. Reading that "changed" my perspective in realizing that there are some people who are possibly beyond redemption of mind; and so - perhaps sadly - I care less and less about reaching older generations with different ideas and tend to focus more on younger generations and the youth, who might not perhaps be as rigid in their beliefs or psychopathic in their indoctrinated "morals". I have also learned a great deal about the "generational gap" in the acceptance of new ideas or the application of labels, in terms of older generations and individuals - who are in their own right VERY intelligent people - being utterly (or at least seemingly) incapable of advancing their own notions and ideas. It is as if they have made up their minds long ago, set in stone, and there is no room for change. That is even evident from the responses in this forum, which immediately took a turn for the ugly with the first post expressing how his ideas have not changed because he willingly remains stoic in his own intellectual capacities. I still have hope for many individuals to eventually change or at least accept new ideas, and I think that some of them will as the world changes itself. That, I think, crosses generations... it's just harder to get to that point.
In this sense, I have learned a great deal from RJ forums, and I think it has played a fairly significant role in advancing and altering my own personal political ideas and beliefs. In some respects, it has literally opened my mind to new ideas and information, and in other respects it has made me more stubborn in certain beliefs, or even unforgiving about certain issues and ideas.
All in all, my answer is... Yes.