There are four broad categories of fake news, according to media professor Melissa Zimdars of Merrimack College.
CATEGORY 1: Fake, false, or regularly misleading websites that are shared on Facebook and social media. Some of these websites may rely on “outrage” by using distorted headlines and decontextualized or dubious information in order to generate likes, shares, and profits.
CATEGORY 2: Websites that may circulate misleading and/or potentially unreliable information
CATEGORY 3: Websites which sometimes use clickbait-y headlines and social media descriptions
CATEGORY 4: Satire/comedy sites, which can offer important critical commentary on politics and society, but have the potential to be shared as actual/literal news
No single topic falls under a single category - for example, false or misleading medical news may be entirely fabricated (Category 1), may intentionally misinterpret facts or misrepresent data (Category 2), may be accurate or partially accurate but use an alarmist title to get your attention (Category 3) or may be a critique on modern medical practice (Category 4.) Some articles fall under more than one category. Assessing the quality of the content is crucial to understanding whether what you are viewing is true or not. It is up to you to do the legwork to make sure your information is good.
Eli Pariser's prescient 2011 TED Talk addresses the dangers of filter bubbles. As web companies strive to tailor their services (including news and search results) to our personal tastes, there's a dangerous unintended consequence: We get trapped in a "filter bubble" and don't get exposed to information that could challenge or broaden our worldview. Pariser argues powerfully that this will ultimately prove to be bad for us and bad for democracy.