Still 4...c6 5.Bc4 exf3 6.Nxc3 might be more precise than 4...exf3 5.Nxf3 c6 6.Bc4 as the first denies White's deviation to play Bd3.
Maybe it is too optimistic, to state that Black is lost after 5...Qa5 6.Bd2, but even Schiller agrees that White has very dangerous compensation.

Forgive me if I demonstrate a lack of BDG erudition.  I bring to the forefront a topic on the O'Kelly Defense of the infamous Blackmar-Diemer Gambit.

The O'Kelly Defense is introduced by the moves

1.d4 d5 2.e4 dxe4 3.Nc3 Nf6 4.f3 c6

This is TopNotch's recommendation against the BDG, which he suggests in the thread "BDG in the Caro-Kann:"  http://altmax.com/cgi-local/cpf/YaBB.cgi?board=dpawnspecials;action=display;num=...

I also noticed that tracke (who also seems to be a fairly strong player) has mentioned that he prefers this line. Furthermore, the line has been recommended by Larry Kaufman in his repertoire book The Chess Advantage in Black and White.

This line strikes me as a very sensible way to counter the Blackmar-Diemer ambitiously without unnecessary risk.  I am somewhat surprised that a topic is not already devoted to this line, since it seems to have an excellent reputation among master-strength players.  For one, the line seems to be very practical as it seeks to overtake the initiative from white.  Also, it does not give white an easy choice to make in decisions involving the development of his pieces, since white is still left with the awkward pawn on f3.  (This is one reason I tend to favor this approach over Prie's recommendation of  3...e5.  Once white is committed to f3, I think black can play more ambitiously.)  Also, there  seems to be less theory and forced lines to remember when compared to the more committal Ziegler (5...c6) or Euwe (5...e6) defenses that arise after immediate acceptance following 4...exf3 5.Nxf3.  These lines may be very good for black, but it seems really impractical to prepare for all the complications of arcane BDG lines like the Alchemy variations of the Zeigler Defense (as analyzed in the Zeigler Defense thread), when there seems to be a simpler solution in the O'Kelly Defense.

When TopNotch posted his recommendation, teyko commented "Why does the Bdg generate so much hate?", but I don't remember any of the BDG supporters defending their case against this line.  I remember teyko commenting that several other lines "lead to forced draws,"  but I don't remember mention of this line.  With all the BDG discussion, the only mention of this line I've seen is by the BDG "haters."  This is particularly odd, since it seems like one of the most practical tries against the BDG (i.e. a line that someone would actually play OTB).  Correct me if I mistaken in thinking this is a promising line for black.

Anyone here to defend the white cause (or further support the black cause   ) ?