List subscribers get justifiably annoyed if these restrictions are flouted, even accidentally, as lists are essentially online communities of professionals in the same field. Sensibly used, not much. The easiest solution is to just delete those postings, but if there are very many of them, it can be irritating. If a list never deals with things that interest you, the best thing to do is to unsubscribe, of course. It's a good idea to apply filters to your emails if you are subscribed to a list, so that your inbox does not become too cluttered, especially if you are on vacation for a spell.
Some lists generate lots of entries every day.
Beware of using 'Reply' facilities of your email software, until you know whether the reply goes to an individual or to the whole list. The potential for embarrassment, or even legal problems such as defamation suits, is there, so it is wise to know well how the list works and to think before you write and act in a professional way. A good rule of thumb is to assume anything you write in any email can be made public, including in a court of law, and write accordingly. Lists come and go to an extent, and wax and wane a bit with time. The following are worth a try, in my view.