Used of a web page that has been specially designed for search engine with the aim of gaining high ranking. It makes it easy for the search engine to follow the links on the page.

a web page designed and optimized for high search engine rankings. Such pages are rich in keywords and structured for ease of crawling.

Compatibility with the way the various major search engines work. Without being search engine friendly a website will be hard to find. A search engine is a business like any other if it does not produce the results it's customers need then market forces dictate it's customers will go elsewhere. Search engine friendliness is attempting to ensure a website "does what it says on the tin" in the eyes of the major search engines.