Google Caffeine Update was released in 2009, this google update is to improve of Indexing system of Search Engine. This Google update is also known as the web Indexing System. This was the amazing systematic procedure of Google which allows Google to crawl webpages. After that also allows to storage of the data of crawled websites.
Now google is capable of crawling, collecting data, and adding in the indexing processor. In those days, First-time Google was able to show fresh content on the SERP world widely.
Google Caffeine was really the new wave of crawling and indexing, Content publishers can publish their information or content on websites, google now faster, and the shows in SERP fast.
In this way, Google web crawlers find new web pages and crawl them for indexing. In this method crawl linked URLs and images and also we can say Caffeine update uses a method of streaming.