On the subject of language and writing, I have long stated that the internet and jargon has "dumbed down" people and they don't know how to spell, or which word is proper to use in a sentence. I can't even being to count the number of times someone has used your when they should have used you're.
I have heard many people make this type of association, but the Internet community is actually developing their own written dialect. Language is fluid and the idea of unchanging norms or standards is not realistic. This is my biggest criticism of formal writing standards.
I agree some people could put more effort into their Internet writing, but many formats on the Internet encourage letter and word economy. I don't know if mixing up
your and
you're necessarily comes from the use of a "short hand", as it is a common mistake even off the Internet.
I do believe computers and the Internet will play a role in how written language is shaped; however, I don't see this as a "dumbing down"; just different. Take for example my spacing and lack of indention in this post. I do that on purpose, because on a discussion forum that has become the accepted style, and it seems easier for people to read off a computer screen.
Grammar should never be a set of unwavering rules; instead grammar is there to help guide us into writing something that the reader can easily interact with.
Personally, I think good writing is more about effort than it is intelligence, and all I want to see in a post is effort. I don't mind grammatical mistakes, as long as they are not due to a lack of effort. I put a lot of effort into my writing and it annoys me when someone wants me to listen to them, but does not want to put effort into their writing.