Ask HN: Are avatars so important?

Hi folks,

me and my friend always asked us, how important avatars are on the websites where people participate in discussions. Nowadays all the forums around uses avatars, all the IM clients uses avatars, skype and so on. Yes, even stackoverflow uses them. So, it seems, that everywhere, where people tend to communicate or maybe interact with each other, avatars are used. (HN doesn't count here, because it goes a really really sparse design paradigm)

However, I also know people which hates them. In some case this is also a good point, since avatars could break the design experience of a website: imagine a pink pig as an avatar on some more serious site, e.g. like stackoverflow. In my case I often just ignore them, however, I found my self putting an avatar representing me on a lot of sites and im-clients.

So, what do you think: How is it important for a website to provide avatars support to their users, if the website is going main stream? What is a benefit of this? Does it increase 'user come-back' ratio? Or is it just a question of: "Everybody uses them, so let us also use them"?

thanks in advance