There are tons. One prominent email provider is a three-digit number. There's a job board at 51job.com.
(What's 51job? Read in Mandarin, that would be "wǔ yāo job" [five one "job" (the English word)]. This is felt to sound similar to "wǒ yào job" 我要job [I want a job].)
幺 yāo is a common word for 1 when vocalizing a stream of digits. (Such as a phone number / credit card number / account number / etc.) I am told that this originated as a way to easily distinguish 1 from 7 (七 qī) when communicating over a low-quality connection. In the presence of static, yi and qi could sound similar.
CC-CEDICT has a good gloss ( https://www.mdbg.net/chinese/dictionary?page=worddict&wdrst=... ):
> one (unambiguous spoken form when spelling out numbers, esp. on telephone or in military)
Also I'm not sure what effect that will have for Chinese users. It might make many of their URLs look strange to them.
See: https://www.reddit.com/r/firefox/comments/7ul9p3/why_is_netw...