Yes I have changed my opinion on a topic. I have not entirely switched to another side before but I almost have done that. I have gained insight into the other side, and that has made me much more educated on the topic. I have changed my mind on so many things about certain topics, though I have never fully switched to the opposing side.
I have not fully changed my side on an opinion, but I have gotten more insight on the other side of the debate, especially the side I do not agree with. That is why I love this site. I enjoy seeing the new points I never though of supporting what I believe in, as well as the opposite sides contentions.
I don't take a side based on what other people believe. I form my own opinion based on the facts from both sides.
Because I know both sides, I have a good idea of what others will or may say and know how to defeat it because I have defeated it before against myself.
I only comment on an issue if I am very much on one side of it. I don't comment if I am just leaning one way.
I sometimes oppose a side I am on, but only if the person give a bad, or faulty argument.
Example: I am an atheist but I sometime go against other atheists who make ignorant comments about religion(s).
My position on a topic has yet to change due to a debate.
To be fair, I have only been on this site for three days.
I have certainly become more informed, and I am enjoying the challenges.
I was tempted to go under the 'yes' column, but so far I have technically not changed my position.