Andrew Lih 2009
Wikipedia is better than Google - if you want to find information searching with a text string or keyword, Wikipedia will look for the string without misinterpretation by Artificial Idiocy. If you do not find the information you want, then you should track it down and add it to Wikipedia.
This book is mostly biographical and historical - it tells us how Jimbo Wales, Larry Sanger, Ward Cunningham, and a cast of millions hyperlinked their way towards a lot of knowledge in one searchable place. Bots (good and bad), advertising (or not), forks, language wars, namewars, vandalism, and the construction of a control system to balance freedom and responsibility. This is about constructing a website and a service, but also about nation building. In fifty years, expect Wikipedia to control land and have an air force :-). Wikipedia is featureful and flawed, but there is raging disagreement about which is which.
The English/American version of Wikipedia is growing but mature - most new growth is in other languages, and accomodating language differences is the New Thing - at least it was when Beijing-based Lih wrote the book. Chinese is at least four written languages (traditional, simplified, Taiwan, "colonies" like Singapore), and required clever programming to share content to these different markets. Perhaps this will expand to serving once-written content to many more languages; a human-assisted translation machine.
My guess is that Wikipedia will mature into a component in a hyperlinked web infrastructure, accessed and expanded by other tools, pointing at other tools. Maintaining predictable interfaces into a fluid tool will be a challenge, but worthy of the talents of all the people contributing.