There is always room for good sentence construction, good grammar, and proper punctuation.
Having said that, I think that in many cases, it is a matter of how easily one types that determines whether or not you use "i" or "I"!
Teaching keyboarding was one of the many things I have done over the years in making a living. When you take keyboarding seriously, (i.e. practice, practice, practice) you develop your skills at typing and move into the realm of being able to use the keyboard without thinking about what your fingers are doing. It then becomes a matter of how well you were schooled in proper punctuation in school.
I know...sounds like a lot of blah blah...I'm laughing at myself for being so serious about it!!!
However, since many people will be making an assessment of who and what you are by the way you communicate, I still think it is important to spend some time honing (sic?) your writing skills.
Hope this isn't too much information!!!