1. From the perspective of URL, the secondary domain name is more trustworthy than the secondary directory in essence. However, from the perspective of search engine ranking, it is recommended to use subdirectories instead of secondary domain names as much as possible.
2. The secondary domain name and the primary domain name are two completely different websites, equivalent to two websites to be promoted. All network marketing work must be carried out again. The public relations value and trust of the website will be separated by the two. The site is decentralized. Using secondary domain names will increase the number of websites, but it will also make the website smaller. Subdirectories will make the website bigger and bigger. A very important point of search engine optimization is the content of the website and the quality and strength of the website itself. The size of the website is one of the most important indicators.
3. For search engines, the secondary domain name belongs to an independent website, while the subdirectory actually belongs to a page under the main website. Secondary domain names and subdirectories have higher weights. Theoretically, the weight of secondary domain names and subdirectories in search engines is not high or low, but they are different for different situations. For newly created subdirectories and secondary domain names, subdirectories are more important because they will inherit the weight of the main website. For the search engine, it is no different from other pages on the website and will be easily included;
The secondary domain name is very important at first, because the secondary domain name is equivalent to a new website. Unless the primary domain name is very high, the secondary domain name is basically similar to a new website. If it wants to be included by search engines. In other words, subdirectories will initially be better than secondary domain names, but they may develop in the opposite direction.