+
+The avatars are provided by various sites. For email addresses, it uses a
+[gravatar](http://gravatar.com/). For a wiki username, the
+user's email address is looked up and the gravatar for that user is
+displayed. (Of course, the user has to have filled in their email address
+on their Preferences page for that to work. Also, when the user changes
+their email address in Preferences, the gravatar won't change until the
+wiki is rebuilt.)
+
+For openid, openavatar sucked and is now dead. So we need to use an email
+address instead, I guess. Problem is that the email address of a given
+openid is only known when that user is logged in and making a change.
+And we don't want to leak an openid user's email into a page either.
+Hmm. Suppose the gravatar hash could be calculated from the email address
+and embedded instead of the openid? That would work for comments,
+but not if the directive were used elsewhere.
+
+Or, for openid, could use <http://paulisageek.com/openidavatar>. Which
+works fine, but users are not likely to figure out what they need to do to
+get an avatar associated with their openid.
+
+---
+
+Alternative, not overdesigned approach:
+
+Modify comments plugin to have an option to display avatars.
+
+When posting a comment, fill in the avatarhash field in the template.
+The hash is calculated from the user's email address. If the user's email
+is not known, skip it.
+
+End. :P
+
+---
+
+[libravatar](https://launchpad.net/libravatar) is a federated avatar
+system. Young but might be the right way to get avatars eventually.