There is no absolute good. Many of these achievements have had negative effects. For instance, American global philanthropism usually comes with strings attached and is often exploited to gain political and cultural influence. But there is no denying that America does a lot of good things around the world, too. Except maybe Russia. But then the ruskies dont deserve it, do they? 
Post anything else you deem as great or greater. Justify yourself.
Television and the remote. One wouldn’t be as good without the other.
The Internet. It wasn’t just the US, but we were instrumental in getting it going.
No poll before. Technilogically, we invented electricity. More specifically, we harnessed electricity. The intent was of course to eventually create television and the remote. Otherwise our greatest contribution has been democracy.
Raising clueless self-importance to an art form?
A poll on this subject which fails to list jazz, barbecue or indoor plumbing is a massive fail.
Fake boobs. I don’t know if the US invented it but whoever invented it deserves praise. I can’t watch tv from the 80’s anymore when women had to wear fake boobs on their shoulders.
But, I think the easy answer here (and not on the poll) would be the lightbulb.
More specifically internet porn. It gives the huddled masses more to yearn for.
Any technological advance would made been made by another country within a few years of its discovery in the U.S.
I will go with something not in the poll: the defeat of the Nazis.
I was thinking about that too but historically, Russians weakened them to the breaking point at the battle of the bulge, and both US and Russian forces arrived in Berlin at the same time. The US led a coalition force as well from the west, it wasn’t 100% US soldiers. I’d actually give the US less than half the credit for Germany’s defeat, but for WW2 overall, US takes the lead by beating Japan.
“Executed the Marshall Plan,” because of its implied “did not execute the Morgenthau Plan.”
We didn’t invent democracy.
BBQ was invented by natives in the Caribbean and Rome had indoor plumbing, so out of that list jazz is the only American invention.
A lot of major health care research has been conducted in the United States.
I think the general consensus is that fake boobs has been a terrible development. But let’s not derail this thread.
Light bulb is a good one.
Collecting donations for and sending foreign aid to tsunami/earthquake victims counts for a lot in my book.
Actually, jazz and blues have roots from African slave music.
I thought BBQ was the funniest, wasn’t that invented roughly the same time as the discovery of fire?
Also, I think only the word “barbeque” came from the carribean, the act of cooking stuff on fire, marinading meat, or smoking meat is thousands of years old.
Fake boobs. TV and remote. Light bulb. Things Americans didn’t invent. Holy crap. Where’s American pride? This is a civilization in decline.
American education system? 
Actually I reread the OP, it doesn’t say it had to have started in the US, otherwise nothing in the poll would count.
I voted for philanthropic efforts, and I specifically had in mind vaccines more than anything else. Dr. Salk could have profited enormously from the polio vaccine, for example, but didn’t.
I don’t know if it’s the greatest contribution (and it is no longer unique) but GPS belongs on the list.