(1) Prerequisites for Alexa browsing rate statistics and ranking
1. Alexa’s website ranking is based on the browsing rate of each specific website. The higher the pageview rate, the higher the ranking.
2. The browsing rate is calculated for the website defined in the domain. For example: www.baidu.com, zhidao.baidu.com and baike.baidu.com will be counted as the same website because they belong to the baidu.com domain. However, there are exceptions, such as personal homepages. If the system can automatically distinguish them from the URL address, they will be regarded as independent websites.
3. Websites providing the same content will be counted as the same website. For example, if Baidu uses two domain names, www.baidu.com and baidu.com, to publish the same content, they will be counted as the same website.
4. The visits included in the statistics only come from users using Alexa Toolbar. That is, only users download the Alexa toolbar and embed it in their browsers. In this way, if the user visits a certain website, the access record can be counted as the number of visits to the visited website. According to Alexa statistics, there are now millions of users using the toolbar.
5. The Alexa toolbar is currently valid for use in Internet Explorer and FireFox browsers, and visits using other browsers will not be counted.
6. When encountering a site with security protection or encryption, the Alexa toolbar will automatically close. Therefore, Alexa will not be able to search and statistically rank those sites with high security factors.
(2) Alexa browsing rate algorithm (Users Reach + Page Views)
1. When a specific website is ranked, the browsing rate data is based on the accumulation of the website's 3-month visit record. That is to say, Alexa releases the ranking results every three months, which is usually called the ranking. Its calculation mainly depends on the number of visiting users (Users Reach) and the number of page views (Page Views). The Alexa system counts the number of users and page views of each website every day, and calculates the current ranking through the geometric mean of the three-month cumulative values of these two quantities.
2. Users Reach refers to the number of people who visit a specific website through the Internet. It is expressed as the ratio of the number of people who visit a specific website to the number of all Internet users. That is: Number of visiting users = (Number of visitors/Number of total Alexa users) * 100%, Alexa uses per million people as the counting unit. Take the WebRoot website directory (www.webroot.org.cn) as an example. If the number of users visiting it is 2%, that is to say, if one million Internet users are randomly selected, 20,000 of them will visit the WebRoot website directory.
3. Page Views (Page Views) refers to how many pages of a specific website a user has visited. It is the sum of the number of pages viewed by all users who visit the website. The average number of pages viewed by each user is the average number of unique pages viewed by all users who visit the website every day. Multiple views of the same page by the same person, on the same day, will only be recorded once.
(3) Analysis of Alexa Ranking Mechanism
Although Alexa provides a lot of valuable information on its website, its real claim to fame is the global website ranking that has been quoted everywhere and hyped many times by the media and has caused huge controversy. According to the "official statement" on the Alexa website, the total global website ranking disclosed by Alexa is a comprehensive ranking calculated by collecting the information returned by all Alexa toolbars. From this "official statement", it is not difficult to see that there are two factors that affect Alexa's ranking. One is the information collected by Alexa, and the other is Alexa's calculation method for deep processing of this information.
On the Alexa website, people can query the number of visitors to a specific website. Alexa provides a data called Reach per million users (referred to as Reach) to represent the number of visitors. This The data refers to the average number of people who visit a website per day per million Alexa Toolbar users. For example, on November 3, 2004, the Reach value of google.com was 178,500. That is to say, on this day, nearly 180,000 of every million Alexa toolbar users visited google.com.
The number of visitors alone is not enough to reflect how much a website is viewed by netizens. Alexa also provides another data to reflect the usage rate of a specific website by visiting netizens. This is PageViews per user (pages viewed per user, referred to as PV). The PV value of a website is the average of the total number of pages viewed on the website by all Alexa toolbar users who visit the website every day, and repeated browsing of the same page by the same person is only counted once per day. Take the visit data of google.com on November 3, 2004 as an example. On this day, the PV value of google.com was 4.0, which means that the visiting netizens browsed an average of 4 pages on the google.com website.
With the two data of Reach and PV, Alexa can rank global websites based on comprehensive traffic. It calls this ranking of websites Traffic Rank (Traffic Ranking, or Rank for short). According to Alexa's explanation on its website, What determines this Rank is the geometric mean of Reach and PV, which is the square root of the product of the two. Obviously, the higher the Reach and PV value of a website, the higher its Rank. Still taking google.com as an example, its PV value of 4.0 is not high for ordinary websites. However, because there are so many users of the Google search engine, its Reach value is much higher than that of ordinary websites, making google.com The Rank reached 3, which means that the global ranking of google.com that day was third. The highest-ranking website in the world is yahoo.com, and its reach and PV values are relatively high among global websites.
Every moment, every computer terminal with the Alexa toolbar installed in the world will report to Alexa the terminal’s access to the Internet. Based on this information, Alexa recalculates the ranking of global websites every day, which means that the Alexa ranking is updated daily. Because almost all websites in the world are within the monitoring scope of Alexa, and this daily updated ranking seems too intuitive, coupled with the fact that it is public data that can be checked at any time, the Alexa ranking appears to be very sensitive on many occasions.
(5) Other factors affecting Alexa ranking
1. The adoption rate of Alexa Toolbar varies around the world and is affected by the user's language, region, culture and other aspects. Therefore, compared with websites in other languages, English website traffic data is easier to fully count.
2. It is easily affected by the extent to which the website promotes itself, the amount of advertising, and the number of links established by other websites for it.
3. Websites of different categories are sometimes not comparable, so comprehensive rankings cannot be compared blindly. For example, professional websites rank very high among websites in the same category, but compared with portal websites, the browsing rate may be very different.
4. It is best for ranked websites to actively add their URL addresses to Alexa, otherwise the traffic statistics will be affected, and Alexa does not provide detailed statistics on the traffic of these websites.
5. Website statistics may be inaccurate if the pageview rate is too small. Generally speaking, the statistics of websites with higher rankings (larger pageview rates) are more reliable. Generally speaking, statistics for websites with less than 1,000 monthly visits or rankings above 100,000 are inaccurate.