* July 28, 2008, so called Google killer Cuil launched its search engine. It claimed that their index of 120B documents was 3x that of any search engine. Three days before though, Google announced it knew of 1 trillion URL's.
* June 3, 2008, Wikia Search launched a feature that allows users to add and delete URL's to search results. July 16, 2008, Google announced that it is bucket testing similar features. The features went live a few months later.
So what's going on here? Greg's reaction to this was that it was atypical of a market leader to be so reactive to "the competition" (if that's what you call companies that have a minuscule share of the market). He's right. Can you imagine Walmart making wholesale changes to its stores because mom and pop's store on the corner implemented some neat features for its customers?
I guess the fact that there are zero switching costs for search engines makes their paranoia run a bit higher than most.....