In case you missed it, Amazon has released a beta version of their new search engine called A9. That's right, Amazon is jumping into the search engine fray by adding their own unique content to the mix. Run a search on A9 and you'll see results from the Google database in addition to relevant extracts from the 120,000 books Amazon has available in full-text. (See Amazon's Amazon.com Opens the Books.) So if a searcher does a web search using A9 he may discover that the best choice is actually a book; and if Amazon sells more books, well that's what I call a win-win situation.
Wouldn't it be cool to have a legal version of A9 that combines a web search with results from electronic books/subscriptions using the Google relevancy ranking, based on how often that book/article is cited. Perhaps it only pulls the information available to you by subscription like a federated search engine, OR maybe publishers could sell pieces of information to a bunch of people instead of the whole enchilada to a select few, similar to what Northern Light was doing a few years back. But I'm getting carried away.
For more information on A9, see Barbara Quint's Newsbreak discussing A9's personalization features and enhancements and
Gary Price's Resourceshelf.