This is from 2004. A lot of the paper still applies, in principle, but I'd argue that there are far fewer people chomping at the bit to get in to the search business these days. Now it's all "social" or "game" related.
Agree and I think there's a a few big opportunities. e.g. a better job search engine. Search in some form is what most of us spend a huge amount of time doing every day. Even searching within web pages for the relevant content we're looking for.
Also Google are barely keeping their head above the web spam and filtering out spam is a very hard problem which may be better solved with a blend of human intelligence. Before you disagree with me consider that there are vast farms of humans creating SEO content and the content-gen business is growing extremely fast.It's the thing that scares Google the most in search.
I'd say if you can provide a better vertical search, say for java/scala programmers, that's s worthwhile endeavor. Also, many folks think Solr / lucene /sphinx is the only game in town, but Riak and indexTank certainly don't buy that.
