PageRank refers to a number that Google calculates and assigns to a Web page based on a number of factors. The actual formula is proprietary and not public. PageRank is a trademark of Google and the name comes from Larry Page, who co-founded Google along with Sergey Brin. The industry knows, or at least strongly believes, that inbound links are one of the most important factors in PageRank.
You can think of links as a way that Google gauges the trustworthiness or importance a site. A link from a site with a high PageRank is more important than a link from a lesser quality site. You can get a rough indication of PageRank with the Google toolbar, which shows a page's rank from 0 (lowest) to 10 (highest). Adding further to the mystery around PageRank, this public number is not the exact PageRank as Google doesn't want to give too much information that might allow others to game the algorithm.
Search rank is a general term that refers to the placement of a particular page on a search engine results page (SERP). If the Web page is on the first page of results for the major search engines (Google, Bing, Yahoo), its search rank is very high for that particular query. Wikipedia, for example, tends to have a very high search rank for most topics because it has a specific page for many niche topics (“Lost Season 6” for example). Proper SEO techniques can help most sites increase their PageRank for a given query.
In Google, having a high PageRank increases your chances of having a high search rank should the query match a webpage topic you cover. This is key, although it's far from the only ranking factor. PageRank is important, and it is a key factor in having high search rank on Google, but it's no guarantee.
- Specific to Google
- Represents the quality of a page and/or domain
- Helps a site climb up the search rank for relevant queries on Google, but isn't the only factor
- General that applies to all search engines
- Refers to the placement of a particular Web page on the search result pages
- Can be improved by SEO