[tommorris]

Yeah, and Wikipedia destroyed the generalist encyclopaedia market. But it created some value for tons of people in the tech business: there's a whole stack of apps on your average smartphone which let you tap a button and get a definition from Wikipedia (or Wiktionary), which makes the phone more useful (and the connectivity packages offered by the telcos more valuable etc.)

Having a useful (for some value of useful) page rather than a spammy viagra-ad-laden page from some low-rent content farm for a few million common queries must make Google happy too.

Value can mean efficiency, and making the market for encyclopedias or classified ads more efficient opens up new opportunities and saves the users of the inefficient services money.