Defiantly Grammar Nazi

So it finally happens.
That, I mean - using 'so' as an opening word.

I mean it's grammatically correct, but it implies laziness on the part of the writer- or an ongoing dialogue, in which the word 'so' is a continuity marker.
It seems to be all the rage, anyways.
I accept that the English language is one of the most dynamic and constantly changing.
 However, what I don't accept is the blatant re-appropriation of entire words and meaning.
I have seen (and used) many forms of slang and differing meanings, but one case that riles me everytime is the word defiantly.
It is currently, popularly in use (certainly online) as a replacement for definitely.
Now, correct me if I'm wrong, but don't the two words have different meanings?
It's fairly obviously laziness on part of the writer somewhere along the line, but continued laziness across the board seems to have led to widespread adoption.
Is this the slow creep of lazy language, or - lingo ?
I thought the term 'bae' was a lazy 'valley girl' shortcut for 'baby' as in 'sweetheart', but likewise it seems to be spreading. I believe it's pronounced as 'bay', in which case, why not just add the extra 'b' for 'baby' ?
Perhaps it's born of auto-correct culture.
I confess, I'm guilty of never using auto-correct as a default, mainly because I hate the frequency with which it suggests wrong words.

a world where everyone communicates in images and colours

I understand that in this multi - cultural world, ease and speed of communications is gained through use of foreshortening and loss of vowels, and I long ago gave up arguing the toss against the 'Americanisation' of words such as colour/color, neighbour/neighbour,aluminium/ aluminum, etc.
But even so, what's the next step ?
If I was a clairvoyant, I might predict a future world where everyone communicates in images and colours.
Nuance could be conveyed in differing shades of colour - which brings me to another point -
We're losing the nuance of words with online media like the global behemoth that is Facebook.
At least here on my blog, I can use italics to emphasize words or even this to strengthen them.

However, in the millions of everyday social media chit-chat texts and messages we now send, it's down to the recipient to try to guess the nuance and intention of  meaning.
Otherwise IT'S SHOUTING.
The loss of nuance equates to the loss of subtlety in language, and that, ultimately, is my gripe.
Where does it end?
Will there be a film entirely in txt spk lol ?