Well, it depends. Over the telephone, or internet, when people can first read or heard my words and think they sound like a pretty good idea. But in person, not so much. If people judge me by looks, I'm sunk. (Not all people do this, though. Most are pretty cool.) I'm middle-aged, overweight, wear dentures, and have been known to have a pronounced Kentucky twang at times, so some people, for whatever reason, seem to think I'm intellectually-challenged. And try influencing someone who thinks they are intellectually superior to you.
For instance, a lot of the people with whom I have come in face-to-face contact during my return to college smile a lot, talk slowly and distinctly. They all but pat my hand and say, "There, there." I used to hear that tone of voice a lot when I worked with adults with mental retardation. I mentally roll my eyes, sigh, and say a prayer for all of us.
The ones I come in contact with by other means (all my classes are online), we're golden. My professors like my writing style, and I've not heard, "Man, you are SO off base,"... yet.
The more passionate I am about a subject, the more likely I am going to be able to influence people on that subject. I believe many people would be the same.