Social media success ia about presenting a positive public face to the world.
I am astonished how many don't get the idea and have written about this topic before.
Here are some examples of the some great avatars mixed with some that just don't give you a friendly feeling.
So who would you rather deal with mr anonymous in the blue gear, the dog, the 'standard'... I didn't put an effort in mr smiley, one of the guys hiding their head, someone in dark glasses, the cartoon chicken or one of the others.
Its all about building trust.