Generally no. However, in some topics they can have an effect.
For instance, if there was an anime thread, like suggestions for good anime, I have an inclination to listen to the person with the anime avatar, because I see that person knowing their shit.
Alternatively, I tend to read more posts of people who's avatar catches my eye. I have no idea who it is, but they have the I am legend avatar with will smith's face scrunched up and it says " god dommit fronk" I make sure to read their posts....always.