Anon. represents anonymous users who use the site without logging in. It is not a user account.

If you have restricted comments to registered users, you can probably find the few users that created most of these comments.

If you upgrade to b2evolution v5, there is an option to delete a user that is considered as a spammer and it will also delete everything else they posted.

Preventing spam comments in general is extremely difficult. It's mostly indian guys now, paid $1 an hour to manually post comments all around the internet. All there's left to do is use software that makes removal of spam much faster than creation of spam. b2evolution v5 is optimized for that.

In v4.1 what you can already so is set new comments to be drafts by default. You will get moderation emails and you can approve or delete each spam message individually as it comes in. This should discourage spammers in the long term because their spam will never show up on the site.

Full answer to "How do I prevent spam comments?" is here:

http://b2evolution.net/man/advanced-topics/fighting-spam/antispam-intro

I am not so much interested in preventing spam comments at the moment. (As you suggested, I have set the default for Comments to Draft.)

*** What I wish to do is to delete all of the comments, spammy or otherwise, we have accumulated. ***

I looked at the v5 change list. It lists: 5.0.0: (doesn't exist); 5.0.1: nothing. I have no desire to work with an alpha product, especially when there is no way to discover even the broad strokes of the features of the new version.

There is a feature called "spam bankruptcy" in b2evo v5 indeed. It kills all comments in a single swoop (you can narrow down by blog and status but below that it kills them all).

The full list of features is coming. It is miles long. We haven't finished compiling the list yet.

I have installed v5.0.4.

Where is the feature to dump/delete all comments and trackbacks?

Dashboard > System > Antispam > Tools

Thank you.