rent a car
Indexing is simply the work the Search Engine Robots do to give you information on rent a car. How does an indexing robot decide what to index? Well they just send their Bots or Spiders to crawl the web looking for rent a car on web sites.
If an indexing robot finds a document that contains rent a car, it may decide to parse it, and insert it into its database. How this is done depends on the robot. Some robots index the HTML Titles that contain rent a car and keep them in their database. Others will look for rent a car in the first few paragraphs, or parse the entire HTML and index all words.
