Spammers threatening sorbs users

Imitating the tactics that were used against Blue Frog users in May, Sorbs users are receiving emails threatening to mailbomb them if they do not stop using Sorbs. One typical email reads as follows:

Hey,

You are recieving this email because you are a member of sorbs
(http://www.sorbs.net).

You signed up because you were expecting to recieve a lesser amount of
spam, unfortunately, due to the tactics used by sorbs, you will end up
recieving this message, or other nonsensical spams 20-40 times more than
you would normally.

How do you make it stop?

Simple, in 48 hours, and every 48 hours thereafter, we will run our
current list of sorbs subscribers through sorbs~Rs database, if you
arent there.. you wont get this again.

We have devised a method to retrieve your address from their database,
so by signing up and remaining a sorbs user not only are you opening
yourself up for this, you are also potentially verifying your email
address through them to even more spammers, and will end up getting up
even more spam as an end-result.

By signing up for sorbs, you are doing the exact opposite of what you
want, so delete your account, and you will stop recieving this.

Why are we doing this?

Its simple, we dont want to, but sorbs is forcing us. We would much
rather not waste our resources and send you these useless mails.

Its simple, we dont want to, but sorbs is forcing us. We would much
rather not waste our resources and send you these useless mails, but do
not believe for one second that we will stop this tirade of emails if you
choose to stay with sorbs.  Just remember one thing when you read this,
we didnt do this to you, sorbs did.

If sorbs decides to play fair, we will do the same.

Just remove yourself from sorbs, and make it easier on you.

As you can see, it is heavily cribbed from the emails sent to Blue Frog users in May.

It remains to be seen how effective these threats will be.