Ran into a new treatment... 1) D4, F5 2) G4, D5 3) C4... I played FxG4 but 

I doubt that is right... white gets a big center with natural moves NC3, BG2 

and E4... What are the strategic ideas for black?

You know, you should use d4 instead of D4. Just a suggestion. And personally, I don't know the dutch.

I haven't encountered any anti-dutch moves so far. (I'm just new here at chess.com but even at live games, still, I haven't encountered them.)

If white tries the Staunton Gambit

I try to be careful on every play, but I'm planning to play d5 on the next move, protecting the e4 pawn.

as for the 2.Nc3 system, here's a sample game

I hope I shared something useful. I don't play the Dutch defense anymore because of the "Flying Dutch Bishop" variation.

you can avoid that move order by playing 1...e6 first before doing the f5 pawn move. But if you play the Leningrad Variation, then the diagram above, you can always play 2...g6

You can just take on g4 and follow up with ..d5, Nf6, Bf5, e6 etc.
There's nothing to worry about.

saw and early h-pawn push in a book once vs. the dutch.

is this playable?

It's playable, but you have to keep in mind that you'll have to play something else if your opponent does not play 3. ..g6 but a stonewall or classical dutch set-up, or even plays 3. ..d6 and only then g6.

2 g4!? is a gimmick gambit.  It's designed to be used as a surprise weapon, because a player confronted with such an unusual idea over the board with a ticking clock is likely not to find the best answer.  Just accept it.  1 d4 f5  2 g4 fxg4  3 e4 d6 (or ...d5, depending on personal style) and Black is basically just a pawn up for  . . . not much.

Whenever someone plays a weird opening or strange gambit against you, first just calm down and remember there is a reason it isn't more popular, and that reason is probably because it isn't any good.  Then figure it out, using the basic principles of opening play you have already learned. 

i justed posted a forum of how to SMASH the dutch a couple hours ago b4 reading this, check it out

I think 2. g4 is tricky, and Black should pay attention.  I think 2...d5 is the best way to handle the g4 gambit. 

Long ago I stumble upon an article about the Dutch defence and the one

that caught my attention was the stonewall variation. Because of its

simplicity I'm hooked on it,and use it often againts d4 by white and obtain

considerable success. To avoid the Staunton gambit I usually start my game

with 1...e6 as advice by that article I've read. But frankly speaking, I don't

have wide reference on this particular variation of the Dutch. Anybody could

enlighten me more? Below was my game I played recently with the Dutch-

stonewall.

No, Black should take first, then play ...d5.  He ends up just a pawn up.  I used to play this gambit, the last time in the early '90s against a 2400 in a postal game.  He took the pawn and held it and I couldn't generate anything, although it took a while for him to grind me down (but the end wasn't in doubt).

Krejcik gambit is a nice way to handle the dutch, I have used it before. If black goes d5 then follow up with g5. But really 2.Nc3 is probably more respectable.

I like an approach I saw once in a book, following up with Bf4 after fxg4...