Hundreds of thousands of web sites use avatars on a daily basis
A large proportion of the images used infringe copyright and have been taken from other websites.
I concede that implementation here would probably prompt extra discussion on these two issues.
It would seem sensible to address those issues before implementation, though.
this is another sad, desperate attempt to cling to the past... don't make them out to be evil
I invite you to accept that an aesthetic preference is not necessarily sad, desperate or clinging.
I have not seen anyone suggest that avatars are evil either.
The suggestion to make viewing avatars optional was well made and nobody has argued against it - I don't even care if you see a generic icon next to my posts with the word "Saddo" emblazoned on it (though some might take the view that putting it in a speech bubble might be more apt).
But the arguments in favour of implementing avatars seem so far to have been "because it is possible", "because I want it" and "because I want to see what other members look like" (meanwhile those pointing out possible drawbacks have been denigrated as "anti-social", "sad", "desperate" and "buzz killingtons").
This is a feedback thread and a good chance to influence the powers-that-be on WebmasterWorld. You need to convince them that there will be positive benefits from a policy change, and you need to address the potential drawbacks that have been raised.
In the absence of other data I just looked at a random thread on the very busy avatar-toting forum of a popular quality publication and got these (admittedly unscientific) results:
Generic "Saddo" avatar - 68%
Copyrighted image - 22%
Text slogan - 4%
Pending approval - 4%
Possible genuine photo of poster - 2%
Interesting to note that all images were pre-moderated.
Assuming that viewing avatars here would be optional I really don't care which way the debate goes.
And I would be happy to see any convincing arguments that actually addressed the issues.