Inconclusive. They might accept a deliverability question. Example threads also include, paraphrased from February archives, "Hey, is peer 1 a spammer network? Yes and no. Here's a list of all their IP space if you want to block them, but you'll probably break something if you do." I'm guessing we had Earthlink deliverability issues even back with Slicehost, so you'd want to ask the question from the Earthlink perspective instead, like you're doing.