Search engine index - links and spiders
You get into a search engine index, not by submission, but by waiting for spiders to crawl your links.
In the past, it was difficult for site owners to add their web pages to the indexes. The submission process was complicated, and often expensive.
These days it is straightforward for site owners to get their web pages indexed. They just provide links from pages that are already indexed.
The spiders simply follow the current links and find the fresh material. Of course, because getting indexed is so easy, many more pages are finding their way on to the web.
Site owners must make sure their pages stand out from the crowd. In a crowd of people, the King stands out & everyone points to him.
Well written content stands out on the web and draws many links.