Multivariate Testing: A type of testing that varies and tests more than one or two campaign elements at a time to determine the best performing elements and combinations. Multivariate testing can gather significant results on many different components of, for example, alternative PPC ad titles or descriptions in a short period of time. Often it requires special expertise to analyze complex statistical results. (Compare to A/B Testing which changes only one element at a time, alternately serving an “old” version ad and a changed ad.) In search advertising, you might do A/B Split or Multivariate testing to learn what parts of a landing page (background color, title, headline, fill in forms, design, images) produce higher conversions and are more cost effective.
Natural or organic listings: The pages listing results from a search engine query which are displayed in a sequence according to relevance of match between the keyword phrase typed into a search engine and a web page according to a ranking algorithm used by the search engine.
Organic search results: These are free search results and are found when searching for keywords in a search engine such as Google. The higher the page ranking a website, the higher the website will rank on the organic search engine results.