John Battelle's predictions for search, rss, blogs and other stuff for 2005 are an interesting read. My eye was caught by number 7:
7. Yahoo and Google will both test systems that combine local merchant inventory information with search, so that merchants can use search as a direct sales channel. By the end of the year, there will be no question that the search companies are in direct competition with the ecommerce companies, but it won't matter - there's room for them all. Paul Ford will continue to get droves of readers to his related, and very prescient, three year old post on how Google takes over the world. [John Battelle's Searchblog: A Look Ahead]
This is a prediction, but we already see, for example, many bookselling sites returning hits in a search.
As more materials get indexed in Google, the page rank algorithm may be less applicable to some than to others. Google Scholar seems to have moved to more of a citation based approach, for example. This will be something to watch ...