Wikipedia

While your high school teachers and college professors may have taught you to doubt Wikipedia’s reliability, its rise to prominence since launching in 2001 is undeniable. With five million English entries, Wikipedia has become the de facto Internet encyclopedia. That said, Wikipedia’s openness — arguably what’s fueled its omnipresence — is also its biggest handicap. Since Wikipedia articles can be edited by anyone with Internet access, the platform is susceptible to bias or outright inaccuracy. But that hasn’t hindered its popularity: according to Amazon’s analytics site Alexa, it’s the fifth most trafficked website globally.