What is a crawler?

A crawler also known as a spider or bot is a program that visits websites and reads their pages and other information in order to create entries for a search engine index.

What is Crawl depth ?

Crawl Depth is the extent to which a search engine indexes pages within a website. Most sites contain multiple pages, which in turn can contain subpages. The pages and subpages grow deeper in a manner similar to the way folders and subfolders (or directories and subdirectories) grow deeper in computer storage.

In general, the further down in the Web site hierarchy a particular page appears, the smaller the chance that it will appear with a high rank in a search engine results page (SERP). A Web site’s home page has a crawl depth of 0 by default. Pages in the same site that are linked directly (with one click) from within the home page have a crawl depth of 1; pages that are linked directly from within crawl-depth-1 pages have a crawl depth of 2, and so on

Google Algorithm names

1. BERT (Upcoming)- Bidirectional Encoder Representations from Transformers
2. Medic (core update) – Impact on Medical Sites
3. YMYL- Your Money Your Life
4. EAT- Expertise, authoritativeness, trustworthiness
5. Hawk- Eyes on duplicate business listings
6. Fred- Random name
7. Possum – Play possum i.e., pretend not to understand what’s going on (regarding Google My
   business listing)
8. RankBrain- a machine-learning artificial intelligence
9. Mobile Friendly
10. Hummingbird- Speed
11. Panda – From Google staffer Navneet Panda
12. Penguin – Initial name “webspam” (no reason for the name change)
13. Pigeon- Pigeon name decided on because this is a local search update and pigeons tend to fly back
    home.
14. Payday – regarding payday loan, pornographic, and other heavily spammed queries.
15. Pirate- copyright reports
16. EMD- Exact Match Domain