Most of the spammy for-profit journals are ignored by serious academics. You wouldn't be caught with one of these on your CV. The big Elsevier ones are a prob

Most of the spammy for-profit journals are ignored by serious academics. You wouldn't be caught with one of these on your CV. The big Elsevier ones are a problem, because they are revered as the good journals. For example, Advances in Math is very highly regarded, in particular in my department. I had promised to be done with Elsevier several years ago, but now my collaborator has spoken with an editor at Advances who suggested we submit there. It's the optimal journal for a number of different reasons. If this paper gets accepted, it strengthens my grant and tenure situation. I can't really justify putting myself at this disadvantage.