What kind of index is Google using here?
fizx: Reverse Aho-Corasick matching.Basically, you store all of your searchable text in a suffix tree.  You then do a depth-first search of the tree for matching strings.http://www.cs.brandeis.edu/~mfc/cs120/papers/ptrees.pdfhttp://en.wikipedia.org/wiki/Aho-Corasick_algorithmhttp://en.wikipedia.org/wiki/Suffix_tree