User generated content is any type of content created by non-professionals or audiences and published via a wide variety of mostly web based media. Typical user generated content valuable to business research includes product or service reviews, help or answer pages, and comment and reaction spaces. A Key concern for evaluating the quality of user generated content is to recognize that the participatory content may not be closely vetted by the hosting Internet service provider or web site as they do not bear liability for deceptive or harmful content. For all intents and purposes, most user generated content is anonymous making it very difficult to gauge accuracy and biases. Relying on crowdsourced user generated content is one way to evaluate the reliability of the content provided. Look for for high volume reviews. A four star item that has been reviewed 400 times, is more likely to be a best bet, than a 5 star item with only 5 reviews. Also relying on user generated content hosted on sites with specialized interests may be more persuasive than relying on general purpose sites.
Examples:
General Purpose Reviews: Amazon
Specialized Review Sites: LibraryThing, RottenTomatoes, Yelp, AngiesList, cnet
General Purpose Advice/Help: YahooAnswers, AskQ&A
Specialized Advice/Help: Investopedia, TripAdvisor