An increasing hazard in science publishing is the increasing number of 'predatory journals'. The term refers to low-quality scientific journals which exist solely to make easy money under the 'author pays' model of publishing. These journals pretend to do peer review and they look and feel like proper academic journals, but in reality they will publish anything to harvest those publication fees. It's a scam, and a successful one given the growth of the number of these journals. The way the scam works is for these journals to solicit papers, to claim they do peer review, then to accept the papers. The authors are billed the article processing and publication fees, and then the paper is published online.
There are multiple dangers in this process. The first and most obvious is that the authors are ripped off - they have effectively just paid for someone to turn there text into a web page. There has been no peer review, no proper scrutiny of the content and the chances are that the paper will be ignored by other academics. If you have a limited budget for publication fees you've just wasted it. If you are starting out in your research career publishing in these journals may seem an easy route to getting some papers to your name, but more knowledgeable colleagues will know what you've done and so the risk is that you damage your career, not enhance it. It is also possible that unscrupulous academics will deliberately use predatory journals to beef up a CV to impress people who don't know about predatory journals - all of which sound eminently respectable to the unsuspecting.
However, the biggest danger is not with academics, but with the general public. Most people are impressed by a paper that is published in a scientific journal. Scammers and snake-oil salesmen can use this to peddle fake medical treatments to desperate patients. Shoddy papers that sound scientifically plausible can be published in predatory journals and then used to convince people that there's some real science behind the scam. If you're not a scientist or someone versed in the medical literature a paper that claims to treat late stage cancer patients and to have miraculous results can be very convincing. The best examples of this are the scammers selling GcMAF as a miracle cure for cancer, autism, AIDS and just about everything else.
How can you, as a reader, verify that the journal paper you are reading is not a piece of junk published in exchange for a few hundred dollars?
A first quality check is to verify that the journal is indexed in PubMed or other database. Most of these predatory journals are not indexed, they are just web sites with no external links and no sign that they are included as part of the medical research community. Not every real medical journal is included in PubMed, but the majority certainly are. Note that Google Scholar does not count as a proper database, it is a search engine and includes all kinds of content, including the junk from these predatory journals.
A second check is to look to see if the journal or the journal publisher is listed by the site Scholarly Open Access (http://scholarlyoa.com/). This site does a great service to us all by keeping tabs on the increasing number of predatory journals and the increasingly sophisticated ways they are going about their scam. For example some of the larger predatory publishers are buying real journals which they take over as a cover for their activities.
A third check is to look at other papers published by the same journal. Are there papers by established authors? Is there good quality content that is highly cited?
The final thing is perhaps the most difficult - especially for desperate patients and their families - it is to remain sceptical. This is tough, I know from my own experience that when the outlook is bleak you cannot help look hope somewhere. The truth is hard to accept that are no miracle cures. And if there were, they would not be published in poor quality, obscure journals of dubious honesty, they would be published in the major journals like Nature, Science and others.
The truth is that building up the skills to navigate an increasingly complex spread of journals and papers takes time and commitment, but it's an important skill if we want to avoid being scammed. There is more than academic rigour at stake, when it comes to medicine, it's lives that are at risk, not reputations.