Deep Web data is any online information which isn't indexed by a search engine (e.g., Google). This means that Deep Web information must be found by opening its source and searching for it there rather than by doing a quick Google search.  Common examples of the Deep Web in everyday life include things like university library archives, results found within travel sites, and so on. Deep Web data usually isn't illegal, and is often linked to things like reputable research and library sources. The Deep Web is radically different than the Dark Web, which is often used to conduct illicit or anonymous activity. When you search for a word or phrase in a search engine like Google, the search engine "crawls" through the Internet to find surface-level results. Since Deep Web content is never part of this surface layer, you can't find Deep Web content by using a traditional search engine. As a precaution, using the Firefox browser will prevent your browsing history from being tracked. This both prevents retroactive searches from interfering with your access to Deep Web materials and ensures a degree of privacy not found in other browsers. As with any browser, your Internet Service Provider (ISP) will still be able to see your browsing activity if they look for it. Many websites have search engines built into them; these search engines are necessary in order to find results not listed on the surface web.  An example of this is Facebook's built-in search engine. You can use Facebook's search bar to find users, pages, and other items that you can't find with Google or similar. Another example includes the search bar found on academic research websites or archives. Again, these resources often aren't discoverable without the aid of the related search bar. DuckDuckGo, found at https://duckduckgo.com/, is a private search engine which can index both surface-level web results and Deep Web resources. While unlikely, you may be able to find a few Deep Web results here.  The main disadvantage to using DuckDuckGo is that popular...

How would you rephrase that briefly using Vietnamese?
Hiểu dữ liệu web chìm thực sự là gì. Nắm được cách thức hoạt động của các công cụ tìm kiếm. Dùng Firefox. Dùng công cụ tìm kiếm chuyên dụng. Thử dùng DuckDuckGo. Xác định cơ sở dữ liệu chuyên biệt. Duyệt web chìm nếu thích.