Crawling is the process by which Googlebot discovers new and updated pages to be added to the Google index.
We use a huge set of computers to fetch (or “crawl”) billions of pages on the web. The program that does the fetching is called Googlebot (also known as a robot, bot, or spider). Googlebot uses an algorithmic process: computer programs determine which sites to crawl, how often, and how many pages to fetch from each site. read more
If your site has been infected, it is generally because some vulnerability has allowed a hacker to take control of your site. The hacker may change the content of the site (for example, to add spam), or add additional pages to the site, usually with the intent of phishing (tricking users into parting with personal and credit card information). Alternatively, they may inject malicious code (malware)—for example, scripts or iFrames that pull content from another website that tries to attack any computer that views the page. The term “malware” covers all sorts of malicious software designed to harm a computer or network. Kinds of malware include (but are not limited to) viruses, worms, spyware, and Trojan horses. Once a site or computer has been compromised, it can be used to host malicious content such as phishing sites (sites designed to trick users into parting with personal and credit card information). Some hackers may even take administrative control over a hacked site. read more