Scandinavian, Anderssen Counter Attack

The heavily analyzed Anderssen Counter Gambit (1. e4 d5 2. exd5 Qxd5 3. Nc3 Qa5 4. d4 e5) offers white and black many opportunities to go wrong. See example games Dahl and Kostic. However, black gets the worst of the Anderssen Counter Gambit with this complex game. Therefore, this aggressive counter attack is not considered entirely sound.
-Logicalchess.com

 I've never heard of this before!  Using my patzer chess analysis, it does seem really risky.  I suppose you could just take the pawn back with your queen, and take it from there?  Regardless whether this helped you or not, feel free to message me and tell me how it's gone for you.  PGN games would also be really interesting.  I wouldn't mind adding this to my Scandinavian Defense arsenal if it has potential.

If you really want to surprise someone, you can play the Portuguese Variation (2...Nf6)!

If that game is the only reason black shouldn´t play it, then I guess it´s worth playing. But I would like to know if other variations in the Anderssen Counter Attack, like 4. Qe2, 4. Qh5, 4. Bb5+, or later alternatives give black decent chances of equality. 

I mean, these lines' success is determined on how they fare in games played by grandmasters, so technically you should play an opening which gives black better chances of equality (or an advantage even).  I play the Scandinavian because it suits my style, and I am comfortable with the positions that emerge from it.  I only used the grandmaster's evaluation to show that at the highest level, it's considered unsound.  There are potentially millions of lines that are unsafe at the grandmaster level because of precise play, but are relatively sound with club level players or what not.  In the end, it's your choice.  I like to base variations I employ on what grandmasters use, as if it is an effective opening for grandmasters in tournament games against other grandmasters, then it is definitlely sound for a player like me.

Although I suppose since your FIDE rating is >2000, you probably are way out of my league and shouldn't take any of my comments to seriously. 

You overestimated my rating by atleast 500 points...although I haven't played in any rated games yet I'm pretty sure I'm <1200.  That's really interesting about how some people study Najdorf/Ruy Lopez extensively and win a lot just from opening.  It's true, 3...Qa5 does get somewhat predictable, but there's still plenty of branching from there after 4.d4.  There's a book on the Portuguese Variation (2...Nf6), and apparently it is quite successful, even at the highest levels.  From the little dense reading I've done on the Scandinavian Defense, it seems like you just need to tread carefully through the opening, and as long as you don't make any poor moves will lead to balanced/winning positions for you in the middle/endgame. 

I remember there was some guy promoting 3...Qd7 on his video, but I'm not sure how it worked out for him.  I'm pretty sure 3...Qe5+ leads to black taking a beating, but you should definitley try some of these out.

 Best of luck to you in your Scandinavian Adventure!!!!  Make sure to keep me updated of how it goes, I'm really interested to see how a higher rated player such as yourself likes the Scandinavian.  Perhaps you could post in your blog some of your experimental games with 2...Nf6 or 3...Qd7! 

someone else asked a somewhat similar question here: http://www.chess.com/forum/view/chess-openings/scandinavian-defence

you might want to connect with them!

also, billwall is the master of these kinds of openings. perhaps ask him? 

When I play white, when Black goes to Qa5, I would play b4.

I 've tried 3.Nf3 to avoid blacks ready variations and it's been O.K. with d4, maybe c4, maybe Be2 etc. But is it advisable? They talk about 3. Nc3 making the queen move again as though it is vital but that might come later or c4 can do the same job.

As playing white, you mustn't defend for an attack of the queen. You must attack it.  You must force Black that he must move his/her queen, while you can easily develop. So probably is Nc3 better (attacks Qd5). And for the same reason, it isn't smart for black to move the Queen to the E-file, because Black can develop  a minor piece again.

 ...why should white play like that? this is totally weird...better play d4

I do find it very interesting phobetor how you can even find ideas for the move that was thought to be so bad 3...Qe5+, if black is going to play with his queen on c7. But personally I always thought that kind of setup to be, tempi or not, rather passive and pleasant to grind down.

Well, estragon, b4 to me doesn't even seem logical, trying to create some kind of trap at all costs it seems, and especially why do this when you can get an easy advantage by playing the normal moves? I think the b file is of rather little value, certainly not worth giving up a pawn for it!