Is the danish gambit sound?

I found an interesting article on Danish Gambit : https://www.chessonly.com/danish-gambit/

The Danish Gambit is Aggro

Well, just look at the analysis. -0.5, -0.6 is basically Stockfish's way of saying that it's dead even but black can push for something.

i could beat you in a fist fight

I once played the Danish Gambit and lost the endgame because of lack of two pawns. Still my favorite gambit, though. I just did not take advantage of the Danish Gambit's good qualities.

I have gone over the Danish Gambit games in the 365 database pretty thoroughly, partly because I sometimes play the opening. Most of the recent master games are Danish Gambit declined. Of those that are accepted, the second pawn is usually declined. When the 2nd pawn is accepted, both pawns are usually given back with the exchange of queens with the Schlechter Defense. 

The gambit is fine if black tries to take and keep both pawns. The problem is that in master play, white doesn't get much of an edge when black doesn't try to take and keep 2 pawns.

The Goring Gambit seems better in general against good players and the Danish can often transpose to the Goring.

The thing is, you're down one or two pawns. But a material deficit doesn't always mean you're in a bad position. In fact in most variations it seems easier than usual to create dangerous threats because of the open files and diagonals you have. It's a matter of taste really, but at higher levels people are more likely to know how to defend properly.

I guess the book on that is that this gambit is advantage black, unless he doesn't know what to do with it.

I played around with your game in the analyzer, and it says black has an advantage until he played 7...Nxe4.  If black had played 7...c6 then (depending on white's play) black can take the knight on c3 with an eye towards playing d5.

There is a video "Crush Everyone with the Danish Gambit" with 600K views. It doesn't mention the Schlechter Defense 5...d5, which is clearly the most critical line after taking 2 pawns. The video seems dishonest,

The main line of the Schlechter Defense, leading to a queen exchange and even material.

I looked in the Masters Database, and 7 times black played 3...d5, 3 times ...dxc3, and once ... d3. The 3 times black took the first time, he did not take the second pawn. However, in the Big Database on 365, the Schlechter Defense 5 ... d5 is by far the most common line after 5.Bxb2.

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Imo, the Danish is just like other aggressive-from-the-get-go openings. Personally, I think it's great, but from what I've been reading, If your ELO is above 1700-1800 ish, then you're opponent can counter it with ease, and take the upper hand. If not, then it's a great opening! So I guess in theory the Danish is unsound and disadvantageous, but, lets be real, unless you're playing at a pretty high level, black probably wouldn't know all the opening theory. Hope this helped!

:tup

I play about 1400 blitz and 1750 rapid, and I have an extremely high win percentage with the Danish gambit. Basically, no one I play knows the Schlecter Defence, giving back both pawns, and few know how to decline it correctly. It is not good against opponents who know the correct defences though.

@62
"It is not good against opponents who know the correct defences"
++ That sums it up.
It is good to overrun weaker players that you should beat anyway.
It is bad against stronger players against whom you need most help.

At the 2000 level yes, but at the 1700 level you can overrun players your own strength with it.

I tend to disagree with the last statement. Say I am playing against a 1000, I want a simple game where he makes blunders and I pick him off. Whilst if I'm playing a 1900, I want to make the game as complicated as possible, so gambits are good to get myself a aggresive attack, because the 1900 will pick me off in a closed, positional games. Generally I think play safe against bad players and just wait for them to blinder, and attack and sacrifice against better players than you.