You know,
grammar is (in part) a matter of convention.
We all agree to capitalize the first person singular subject
pronoun, and all is fine. If you don't agree, you incur the
penalties associated with being pointlessly original.
IMHO, those conventions are handy. Anytime I see that big
I thing, I recognize it immediately.
Anyway, it is not a holy matter: one could as well start
writing "y" instead of "and" - it is much shorter, isn't it ?
So let us not look for bullshit reasons like "Ooooh, the Shift key
is so terribly far from my little fingers on this big
keyboard".
I mean, one could as well drop punctuation ... - it boils
down to attitude. You don't capitalize that pronoun? The message that
comes across is that you don't give a damn about other people's
reading convenience. And perhaps, you are so convinced of the
excellence of your thoughts that you do not even try
to package them well.
This is of course a dangerous attitude, as many corporate
web site designers have discovered.