Although a few people here have already said what I would have anyway, I'll just put in my two cents.
The world isn't getting dumber, this generation is just... different. Also, the idea that we have the smallest vocabulary since caveman times is a ridiculous accusation. Honestly, I cannot agree with anyone who says this, because when you look at it, we just abbreviate things more, we know the words, we just try simplifying them.
Unfortunately, I agree.
Why it must be "YOLO####" Instead of "You only live once"? Because of the one second difference while saying it? Oy Vey Zmir... [Yiddish]
I HATE IT.
Plus, it makes some idiotic trends like crapping with an open door, taking a picture of it and write down "YOLO## LOL"... Sheer stupidity.
Again, with YOLO, people are just shortening it, although I myself don't see the reason. Now, as for that last part... that's not the ENTIRE GENERATION, that's just some kids online thinking they're cool and making themselves look like absolute fools. There are a ton of stupid trends out there, but we don't have to follow them. Hence, I disagree, because many in this generation are smart, not all are, but we're not getting any dumber, just... adapting to technology in a way.
Look at people doing all this YOLO stuff, most of them are on a phone, it's darn hard to write on a phone (for me, anyway). Thus, they simplify the typing to shorten the amount of time needed to write and lower the effort needed. Not dumber, just... simpler.
Every time I post in these topics I wonder if I I said what I meant to. XD