there's nothing new under the sun- the saying goes.
The long marching trend is to put all indexable searchable information online broken down to finer sets of particularity then create interfaces to the search functionality.
For general search u gat google. For books amazon, for local books search (*enter local amazon clone*), its coming to taxis, for ppl u gat facebook, for hotels (*too many to mention*), for consumer goods jumia, best bargain - groupon and clones. The whole stuff is just about gathering data, indexing and searching - on a bigger scale.