I read tons of posts from tons of forums and I never see people say, "hey, you know what, I never thought of it like that, maybe you are correct. Maybe there is more research I could do on this subject".....or "that is a valid point, I will incorporate that into my argument the next time I debate someone"...or "well, that certainly is another way to look at it. I guess a solution would be somewhere in the middle of where we both stand"....
Generally speaking, it's never that fast. People not only have egos but have a few decades of thought (for better or worse) backing up their opinions.
Most are not quick to change them - either through simply stubbornness or to an intelligence that requires them to think through all the ramifications and do a little more research on the side.
But ideas are powerful. And you'll find that over time, they do have an affect, and that people will slowly be swayed by powerful arguments or powerful propaganda, depending on their mental makeup.
As a point of fact, I'm still searching for the user that used to have this fantastic sig at the bottom of his posts - it was about a paragraph long, and put forth welfare programs as an example of a way to quell rebellion - that is, the very people that should be up in arms become dependent on the system. If you know of who I speak, please pass that along via PM to me because it was a well written meme.
Part of the issue will always be that people have different definitions of words. For example, most here view any sort of income equality as 'theft' - so, for example, taxation is theft. This is a very understandable position to have - taking money from someone through implied force (via IRS) certainly does seem like theft. But when communicating with the left, the communication tends to break down. For example, for the very far left, one semi-famous statement is that 'property is theft' - that is, claiming ownership of what could be shared by all is theft from the public. This is a simplification, of course, in the same way that 'taxation is theft' is a simplification. Or, that some believe in order to truly have 'freedom' there must be some level of income equality - on an island nation of 100 where 1 man is rich and 99 work for him, 'freedom' is somewhat illusionary. So here we all are, arguing ideas and our words mean different things. Hilarity (aka flamewars) ensues.
But I'm not here to hijack the thread and get philosophical. My point is more to point out that understanding different philosophies is extremely important - you can't even begin to discuss an issue with someone, let alone win them over, if you're not talking about the same thing. Case in point, the posters on this board that curse Kucinich, etc, as 'socialists' and rail against them.