This includes Internet forums or blogs. Unfortunately, you don't read about this sort of thing because the writer is liable to be sued if he or she makes “defamatory remarks.” Watch closely for anything in the contract impeding your First Amendment right to state your opinion about your experience with a publisher. (Of course don't take that as the right to spread lies.)
The only exception I am inclined to make is if it is a traditional publishing company with best-selling authors on its published list and you are being published through their main imprint for a huge advance. Then you are dealing with a professional company and expect to go through professional routes to clear up any grievances.
Another facet to this scam is a company trying to intimidate authors who complain about their services. I worked for an author who published with a certain notorious company that scams authors. She didn't read the fine print or research the company so the realization that she wasn't going to sell millions of books was hard for her. She complained to the company about their business practices and she got an Email demanding an apology for her opinions! I'm proud to report that she didn't apologize for stating her mind. Intimidation to keep authors in their place is not a flattering tactic for a publisher to use.
Make sure you don't sign anything with any language implying you can be sued for stating your opinion on their services and if the contract has a clause like that, consider a different publisher.