Telepolis, magazin der netzkultur, reports on how Chinese communicate with each other in online chat rooms: Du bist ein 286 (You are a 286) by Weigui Fang. (Thanks to Ingmar Greil).

Here’s an example (my translation follows):

bq. Gestern abend kam mein GG [gege: Bruder] mit seinem GF [girl friend] zu uns zum Abendessen. Wie GG und GF bei Tisch meiner Mutter PMP [pai mapi: schmeichelten], war wirklich sehr BT [biantai: abnormal]. 7456 [Es hat mich wirklich geärgert]. Ich hab nur sehr wenig gegessen und sagte 886 [Tschüß] zu ihnen. Dann ging ich ins Internet, um mit meiner MM [meimei: Freundin/kleinen Schwester] zu chatten

bq. Yesterday evening my brother [gege: brother] and his GF [girl friend] came to have dinner with us. It was really quite BT [biantai: abnormal], the way GG and GF PMP [pai mapi: flattered] my mother at table. 7456 [It really annoyed me]. I ate very little and said 886 [Bye] to them. Then I went into the Internet to chat with my MM [meimei: girl friend / little sister.]

About 2000 new words have been invented for the Internet. If you use any method for entering characters onscreen, you will be entering pinyin or code, and you are offered a list of sets of characters to choose from. Internet chat will take, say, the second word from this list, even if it means ‘prawn’, to mean something completely different, because it’s easy to enter and they don’t expect to be needing the word ‘prawn’ in their conversation. Numbers are also used (see the example) where they sound something like the word intended.

Here’s an article on the subject in English.

bq. One of the most common Chinese Internet shorthands is 88, which reads “ba ba” in Chinese and has come to mean “bye bye”.
“If you’re in an Internet cafe and have to rush to class, it’s easier to type 88 than ‘bye’ or ‘zai jian’ (the Chinese word for goodbye),” said Zhou Xizhou, a native of Hunan Province.