I missed the memo on this one...when answering questions, I've noticed recently, people are starting their replies with..."So".
Who's bright idea was this?...
"Ummm" was a better response, I think...It implies they are putting some effort into thinking of an answer.
"So" sound too cocky...the appearance of having an answer without any real knowledge.
end of rant...carry on.

Uh, um, soooo you're pizzed at da way peoples use english???

I think it's like the "I know, right" thing that every one seems to be using to denote agreement. It's just another passing fad, give it a few years and it will be replaced with something else, possibly even more annoying.

It is, so

Ummmm......

So what...

JMO, but I think you have mistaken a subtle shift in the "social breed" of people with whom you have begun interacting, with the emergence of a fad mode of speech.

By the way, I know a few people who, as you describe, habitually start a large number of sentences with the word "So."

I refer to them as "So-sayers," a sort of (very) mildly amusing play on "soothsayers."

One of them is my ex-wife, who's "so-saying" was one of the constant irritants to our relationship.

So, the OP wants everyone to not say so.

But I say it is so!

Yes Goddess...ready for inspection.

So you think the English lingo can do without the word "so"?
I so not agree with you, although I must say I tend to use 'so' too much, I sometimes have to rephrase sentences so (there we go again) I can get rid of that annoying word "so".
But there's worse words / expressions. Guess we all have our pet peeves.

I thoroughly hate it when someone shouts "Oy!"
I think that's a typical English thing, not US. Few things P me O, but Oy! does the trick.

Americans on here often use "just saying"...
Dang, I so hate that! (there it is again!) Almost more than Oy!

So yeah... (there's that word again), we all have things that P us O.
So what? (there's it is again)

What do you have against Mel Brooks?

SOOIE
We use that, instead of that other "s" word.
We are quite progressive, in my neck of the woods.

In the headline it's noting "So?" and "Soooooooo."

Those seem to be requests for a point, a conclusion, more information.

Online they tend to be used in place of (or with it implied) "what's your point?" or "is there a question here?" or "why are you posting this?"

Most forum threads have a purpose, are inquisitive and by nature start discussions. e.g. "Are you going to vote for Hillary or Trump? Anyone ever been to Senior Froggy's all you can eat tacos? What do you think of my profile? What's your favorite movie? Why do nice guys finish last?"

Other forum threads or posts are people masturbating themselves mentally or emotionally. "I just need to argue/rant/vent!"
Only it's not always clear to everyone that they are ranting/venting.

When there seems to be no real purpose or conclusion to a thread, people ask to be supplied with one.

So, (which is used here to begin drawing attention back to the original question being answered, making this post relevant in its entirety rather than disparate and unconnected paragraphs) it was no ones bright idea, the use of "so?" and "soooooo" have been around for a very long time.

For years many teachers have enjoyed using the terms while grading papers. When their students haven't come to a proper conclusion or point that they should have, or provided information that doesn't fit in with the thesis or purpose of the paper.

You reap what you sow.

Oy vey!

I don't think so!