I think it is too common. 'Wanna' to me is particularly bad - it sounds like a child whining for something. As others have said - abbreviations are fine for txting or chatting with friends, but if you are asking for help, surely that is where you should be at least a bit formal and polite, and 'wanna' is far from polite.

It seems to be accepted but it's probably not very helpful for the language learner. Personally, I would use chatspeak only for phone texting, and in a language that I already know how to write without mistakes.

Great question, Yangyang. One person here called it 'chatspeak' -- I call it 'chat-lish'. (Not to be confused with ching-lish, which is ok and part of the learning process :) The only time I can 'accept' chat-lish is if the person is on a mobile phone, thumb-typing. Otherwise, if our contact is to develop proper English skills, I want to see English words, capital letters, and properly spaced punctuation. I text full-sentence answers that way (ok ... 99% of the time), and I do everything I can to help my contacts make a good-faith effort to do the same. So of course, it annoys me to see those 'words' in notebook entries and questions. Maybe I'm "shoveling sand against the tide".

'u', 'ur', having lowercase letters because people are lazy to type the capitalization of the letter is the "internet or texting language". I wouldn't use it when learning a new language. Its not appropriate when writing formal letter or essays, but acceptable in a non formal message to friends and other people in that sense.

Luckily, it is not very common.