An anonymous reader asks: "I guess by now we can be fairly certain that search engines are here to stay, and hence I'm trying to understand how the technology works. I'm not so much looking for a particular 'best' technology or implementation, but rather an overview of the different approaches and their trade-offs. Something that would teach me: which approach works in a distributed vs a centralized infrastructure; how different algorithms will perform on complete search words vs arbitrary sub-strings; or how mass storage (hard disk vs. solid state) affects implementation choices. For most mature technologies there is a host of 'overview' books and papers for my questions -- but I couldn't find anything on search engines. Where should I look? Are there any good books or papers?"