Wikipedia is a website encyclopedia wiki project that uses widespread collaboration to form articles and definitions on variety of topics, including 2.7 million articles in English and 12 million in Wikipedia's total supported languages. Viewers can read articles, edit definitions they disagree with, and create new topics themselves in a process intended to form a collective consensus. Users can access Wikipedia as an encyclopedia, a news source, or a marketing tool, but without peer-review processes or appeal to authority the website has some inherent unreliability. Contributors to Wikipedia can be formally registered or free agents, but bot programs have been programmed into the system to detect and eliminate vandalism, while editors work to modify, delete, or annotate articles to improve consistency and remove bias. Wikipedia has also released a mobile version of its website.