Some focus on phonetic search or various other voice indexing technologies whose accuracy rate depends on the quality of the line recording, the language spoken and the dialect.
That long tail includes about a hundred databases of specialized information that the search engine is now working on indexing, such as the Security and Exchange Commission's online filings and the online collection of medical journals known as PubMed.
Alongside the growing sophistication of net users is a lack of awareness about paid-for results that many search engines provide alongside lists of websites found by indexing the web.
Drummond, whose search company avoids some of these complexities by tapping humans to do its indexing, notes that it would possible to simplify the problem and merely determine, for example, whether or not the Web application has made a data request to Facebook.