Definitely off topic. Perhaps the mods will move the punctuation posts to the Popular Media forum where they belong.
But so long as we are off topic, I think the following general rules of internet communications apply:
Texting via cell phone: Lack of capitalization and use of short hand (number ‘4’ instead of word ‘for’) is acceptable due to the high difficulty of using a phone pad.
Instant messaging (via computer): It’s a private conversation and not subject to the usual rules of grammar beyond what are needed for understanding.
Computer Chat rooms: These are semi-public conversation so proper grammar, spelling, and word usage are considered a sign of intelligence. However typing speed is of importance and sometimes that need trumps the desirability for proper grammar.
Computer message boards/forums: These are semi-public conversation so proper grammar, spelling, and word usage are considered a sign of intelligence and respect to one’s readers. The proper use of the English language is understood to be an element used in judging the maturity of the poster and the importance of the post.
Computer Blogs: These are public forms of communication. The individual is free to express himself (within the guidelines of the service providing the blog space) as he sees fit. He should be prepared to be judged by his writing style.
Email: Email practically demands a set of rules unto itself. Here are a few:
‘Private’ emails are like any written communication as far as writing style. Emails sent to groups are likely to reflect on the sender’s intelligence in a fashion similar to message boards. Forwarded emails should be edited. Readers generally do not want to wade through ten levels of forwarding addresses before getting to the main body of the email. Sometimes the body of the email needs to be edited to remove characters added as a result of forwarding. When sending emails to a number of people or when forwarding emails, one should try to respect the desires of some to keep their email addresses private.