The snippets that appear below the header tags in the search results are is what basically called a Schema. It is a form of microdata that allows the users to get a glimpse of the main content of your website on the Search Engine Result Pages.
Considered to be a structured data vocabulary, the schema is used for the advanced understanding of the human language by the machines. It has the same purpose as the Rankbrain; to make the process of internet searching easy for humans by making the machines more intelligent.
The schema contains a vocabulary that helps it in understanding the word vectors. Applying the schema on your website helps in making it more understandable for users as well as Google and increases its’ chances of ranking higher in SEO ranking.
Spider on the other hand is an internet program that crawls through the websites reading their content and collecting the data to create entries for search engine indexes. This program is a little different from the bots that are used by Google and the other search engines.
The function that distinguishes it is that it is designed to crawl only in that website that has been submitted under the tag of new or updated. This way the labor is divided between the machines as well so the search engines can provide a more accurate service to the users.
Spider has many legs in this program too, which helps it in crawling through multiple websites at the same time. It follows hypertext links on a website which keeps it leading to the other web pages until the entire website has been crawled.
But when it comes to attracting the largest amount of organic traffic on your website, it is the Parasites that is considered to be the most effective method for that.
When a major website that has been doing well in SEO allows the users to post content on it or create a web page, they are considered parasites feeding on the popularity of an already popular and successful website.
To make a profit on your own, you can provide a backlink to your website on the webpage created on the popular website so that the audience impressed with your content can visit your main website and the traffic on it grows. The parasite technique is used when a website is in urgent need of an audience for its content.
