If, for whatever reason, you've ever spent much time on Chinese websites, you'll know that they often use numbers over letters or other characters. So, 4399.com is a gaming site, 92.com deals with car trading, and 12306.cn sells train tickets. Why is that?
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.
And what's more, the strings of numbers aren't random, either: they often link to the service of the site, or act as homophones for other words. So, Internet company NetEase uses 163.com which is a throwback to the days of dial-up when Chinese Internet users had to enter 163 to get online, while e-commerce site Alibaba is 1688.com, which sounds like "yow-leeyoh-ba-ba" out loud. Which is almost right, at least.