In short Search engines like Google, Yahoo! and MSN occasionally change their algorithms as they seek to improve the accuracy and relevance of their search results by implementing new, refined technology. Search engines also may alter their ranking algorithms in an attempt to counter search engine spamming as spam become more advanced; so, too, must the search engines. Occasionally, search engines' algorithm changes can cause panic on the Internet as rankings can fluctuate and some pages will suffer significant drops in their rankings (others will see large improvements) seemingly from one day to the next. The so-called Google Dances, which usually occur a few times each year, refer to the fluctuating search results that are caused by revisions to the search engine's algorithmic ranking procedures.
