Search Engines and their Public Interfaces: Which APIs are the Most Synchronized?
Researchers of commercial search engines often collect data using the application programming interface (API) or by "scraping" results from the web user interface (WUI), but anecdotal evidence suggests the interfaces produce different results. We provide the first in depth quantitative analysis of the results produced by the Google, MSN and Yahoo API and WUI interfaces. After submitting a variety of queries to the interfaces for 5 months, we found significant discrepancies in several categories. Our findings suggest that the API indexes are not older, but they are probably smaller for Google and Yahoo. Researchers may use our findings to better understand the differences between the interfaces and choose the best API for their particular type of queries.