WebProNews

The search engine and portal company indexes nearly double the items its rival, Google, does.

A post in Yahoo's search blog touted the size of the company's index of items. Some 19.2 billion web pages and documents fill the index, along with 1.6 billion images. It is estimated that Google indexes around 11 billion items.

Index size doesn't necessarily translate to quality search results. The entry in Yahoo's search blog says they measure quality with four factors: relevance, comprehensiveness, freshness, and presentation. It further notes how Search Engine Watch has recognized their work with an Outstanding Search Service award.

The topic of search engines, especially with the Search Engine Strategies conference going on in San Jose this week, comes up frequently in the WebProNews lead-lined editorial room. Some writers prefer Yahoo's search results; others like me prefer Google.

If relevance is so important to search engines, why does one person find an engine more relevant in its results than another engine? Is relevance a state of mind? It's a question that can't be answered today, because the various algorithms used to drive search results exist as proprietary holdings.

Without transparency, that is, a way to determine why a search engine finds a given set of results relevant for a query, there's just no way to know. Metasearch site Dogpile noted in a whitepaper that research found only 1.1 percent of first page results across Google, Yahoo, MSN Search, and Ask Jeeves were the same.

David Utter is a staff writer for WebProNews covering technology and business. Email him here.