Gravatars without email all end up looking generic

[thecodepro]

When your blog has this option turned on

"Comment author must fill out name and e-mail"

and multiple users leave comments, if these users do not provide email addresses it will appear that they are all the same user as the identicon/monsterid/etc icons will be the same.

With two additional lines of code, you can substitute the IP address in place of the email to get a unique hash in order to distinguish one anonymous/non-emailed user from another.

Patch is attached

[thecodepro]

adds code to use IP address if email is empty for gravatar handoff

[hakre]

Isn't it possible to reverse-engeneer the comment's authors IP-address then? Some hashing needed?

[thecodepro]

Yes, I suppose you could use a rainbow table to reverse the IP address for anonymous posters.

Could probably salt this with on of those constants defined in wp-config.php if you wanted to make it UBER secure.

I'll look into that real quick...

[thecodepro]

Same as before, but using the NONCE key to obsucre the IP from rainbow reading

[chriscct7]

This would probably be better suited as a plugin which can simply filter the get_gravatar function and if the user's email address doesn't return a gravatar then implement the above idea.

[rachelbaker]

I don't think the use case is broad enough to warrant a core change the default avatar display. Without any real activity in 6 years, I am closing this as a wontfix.