Originally Posted by CatsinDenver
We write in order to communicate. The reason that each language has a set of rules (spelling and grammar) is to facilitate communication. If every person wrote in his or her own made-up language, communication would be difficult or impossible.
Now, I suppose that if someone is using language as an abstract art form, that person wouldn't care much about the communication angle. But I haven't seen any posts here that appear to be intended as experimental prose poetry.
Karen's right--it's common courtesy to make some effort to use correct spelling and grammar. Nobody expects perfection, and I think people here are more than willing to make substantial allowances for those with language difficulties of any kind (although, as has been noted, members for whom English is a second language generally put us native speakers to shame).
Also, keep in mind that good writing habits aren't something that a person can easily switch on and off. If you don't know how to spell a word when using it online, how are you going to know how to spell it when filling out college or job applications? And if you have someone else correct (or write) your application, what are you going to do when you have to write an essay exam or a business letter?
I work in a writing/editorial position for a company that hires many writers/editors. I'm astounded that many people who apply for those positions submit resumes that contain spelling errors. And no, they don't get hired.