An American friend living in Beijing once said she refused to communicate with anyone whose email address consisted of a string of numbers, such as 62718298454@163.com. This made sense to me at the time—why make email addresses as difficult to remember as phone numbers? But I soon realized that issuing a blanket ban on number-based communications would mean cutting off just about every single Chinese person I knew.

In the U.S., you really only have to remember two long numbers, ever: Your phone number and your Social Security number. In China, you’re constantly barraged by digits: QQ numbers (QQ is China’s most popular chat service), email addresses, and even URLs. For example, the massive online retailer Jingdong Mall is at jd.com or, if that takes too long to type, 3.cn. Check out 4399.com to see one of China’s first and largest online gaming websites. Buy and sell used cars at 92.com. Want to purchase train tickets? It’s as easy as 12306.cn.

Why the preference for digits over letters? It mostly has to do with ease of memorization. To a native English-speaker, remembering a long string of digits might seem harder than memorizing a word. But that’s if you understand the word. For many Chinese, numbers are easier to remember than Latin characters. Sure, Chinese children learn the pinyin system that uses the Roman alphabet to spell out Mandarin words (for example, the word for “Internet,” 网络, is spelled wangluo in pinyin). And yes, Arabic numerals (1-2-3) are technically just as much a foreign import as the Roman alphabet (A-B-C). But most Chinese are more familiar with numbers than letters, especially those who didn’t go to college. To many, “Hotmail.com” might as well be Cyrillic.

The digits in a domain name usually aren’t random. The Internet company NetEase uses the web address 163.com—a throwback to the days of dial-up when Chinese Internet users had to enter 163 to get online. The phone companies China Telecom and China Unicom simply reappropriated their well-known customer service numbers as domain names, 10086.cn and 10010.cn, respectively.

Digits are even more convenient when you consider that the words for numbers are homophones for other words. The URL for the massive e-commerce site Alibaba, for example, is 1688.com, pronounced “yow-leeyoh-ba-ba”—close enough! Those digits can just as often have individual meanings. The video sharing site 6.cn works because the word for “six” is a near-homophone for the word “to stream.” The number five is pronounced wu, which sounds like wo, which means “I.” The number one is pronounced yao, which with a different tone means “want.” So the job-hunting site 51job.com sounds a lot like “I want a job.” Likewise, to order McDonalds’ delivery online, just go to 4008-517-517.com, the “517” of which sounds a bit like “I want to eat.” (An English equivalent might be the old radio jingle, “How many cookies did Andrew eat? Andrew 8-8000.”)