What does "No chatroom lingo, please!" mean?

I saw this phrase on these forums for my first time - I’ve never seen it before anywhere. I understand it is some abbreviation of a sort and must not be used in formal stituations, but I’m just interested. If someone cared to explain, I would be grateful.

A lot of people confuse forums with chatrooms. In a chatroom people usually use words that don’t exist such as ‘u’, ‘i’, ‘ur’, etc. Every time a forum user types ‘ur’ instead of ‘your’, our software replaces ‘ur’ with the phrase ‘No chatroom lingo, please!’

Most of our forum users want to improve their English which means they need to develop the habit of following very basic and elementary rules. If someone is not capable of typing ‘your’ or ‘English’ they really should ask how serious they are about learning English.

For more information on this topic, please read How can I improve my writing skills?

Many thanks,

TOEIC listening, question-response: Could I see your driver’s license?[YSaerTTEW443543]

Ok, I understand, thanks a lot Mr. Torsten!

hi anju how r u