The benefit for Public Libraries is that by their very nature Wiki's are a community resource offering an inclusive environment, as does the Library itself. They could be useful for debates, team projects, sharing resources, research collections, book reviews, Bookclubs, community projects and so on.
When discussing Wiki it is almost necessary to mention Wikipedia - the largest and greatest encyclopedia ever compiled. Mind you, the Wikipedia is not error free - but then nor is the Encylopedia Britannica. In fact, in 1964, a physicist called Dr Harvey Einbinder read the Britannica from cover to cover and found enough mistakes to fill a 390-page book, The Myth of the Britannica. Nonetheless, thanks in part to Wikipedia, the satisfaction of curiosity has never been so easy to fulfil.
In this Information Age (or should that be the Age of Information Overload?) it would be reasonable to quote Thomas Edison - "We don't know a millionth of one per cent about anything". And it is no wonder when you consider that back in 1987 it was calculated that a year's worth of daily editions of The New York Times contained more information than a man or woman in the 17th century was likely to encounter in an entire lifetime. And this was long before Google, Wikipedia, Facebook and YouTube.