I wrote this article over 3 years ago, while working at Microsoft. Ironically, I now work at Google. I haven't analyzed the numbers again since then, but I suspect the trends and reasoning are still the same.
I was surprised and delighted to see thousands of hits coming from HackerNews...more than 3 years later. Several search startup CEOs told me they showed this blog post to their VCs while raising money. Pretty cool.
Search is much harder than it looks. The "table stakes" investment required to operate a real search engine have escalated significantly since I wrote this. The competition is tougher, and winning just 1% market share is very, very difficult.
The new markets for search are hyper-local search, mobile search, social filtered search, and search automated action like Siri. Market share might be easier to win in these markets.
Don