Effective communication is the import thing. Not perfect use of grammar. Clearly, very poor grammar can undermine effective communication. It simply has to be good enough (fit for purpose). In longer articles and novels, there is almost certainly a need for better grammar than in short postings on social networks otherwise too much effort is needed to simply understand the text rather than the content.
The internet allows wide and free communication amongst vast numbers of people, many who do not have the dominate internet language of English as their first language. (Having said that, I have found many who have English as a second or third language have a much better understanding and capability with English grammar than many native speakers of English, myself included). We would all be much poorer were we to exclude from the information exchanges those who are less good at English than ourselves.
That said, I still get very irritated when I see my fingers typed there instead of their when I no the difference perfectly well (I am concerned that others might not realise I do) especially on systems that do not let you edit your posts (e.g. Facebook). I am pleased to say that I have stopped gettings irritated by notices such as "5 items or less" (rather than "5 items or fewer") at some shop tills and I really do not care about the splitting of infinitives.
English has always been a dynamic, rapidly evolving and flexible language. I like it that way.
via Public RSS-Feed of Stuart Moore. Created with the PIXELMECHANICS ‘GPlusRSS-Webtool’ at http://gplusrss.com https://plus.google.com/108083406947097710872/posts/NiKyzDaQQag