I am a (relatively) young twenty-something. It's fine to bend conventional grammar and spelling in quick, casual conversations between friends, but not when some degree of formality is required. Many people can switch registers depending on the situation.
Texts and tweets are restricted to 160 and 140 characters respectively. Abbreviations and creative re-spellings were likely invented out of necessity.
Yahoo is open to members of all ages. Some people have their spell-checker set to a different language. Others aren't native English speakers. There will always be a range of spelling and grammar styles here.
Unlike dictionaries, I suspect that spell-check encourages people to mix similar words (e.g. poured/pored, their/there/they're, piqued/peaked and even shuttered/shuddered!). If spell-check doesn't detect it, it must be correct, right?
In all seriousness, some text-speech may be standard in a hundred years. The Oxford Dictionary already includes "OMG" and "LOL."
http://www.oed.com/view/Entry/291168
For a historical example, "hello" wasn't spelt with an 'e' until the 1800's. It was only proper to use it on the telephone, not face-to-face. By the 1920's, one lady felt it could be used to greet a very intimate friend on very informal occasions only.
http://books.google.ca/books?pg=PA19&dq=emily+post+hello&client=firefox-a&id=HhAYAAAAIAAJ&redir_esc=y#v=onepage&q=&f=false
Fast forward to the present and young people are starting to LOL face-to-face with their friends. It still sounds very informal. Perhaps grandmothers will LOL with their grandchildren in 2100. It's rather disturbing to think about.
==========
I would like to disagree with the last part of Sasi's comment below. No teacher promotes swear words, slang or text-speak, yet children still learn them from their peers. Therefore, those who acquire sound English do so in spite of everything they are exposed to. Children are also taught that slang, swearing, etc. are inappropriate. However, there are no editors proofreading private conversations. Non-standard English will survive there.